The most common mistake new managers make in their first 90 days is trying to manage the way their old manager did, whether that manager was good or bad. Some copy what worked for a leader they admired. Others unconsciously repeat patterns from someone who made their working life difficult. Either way, the mistake is the same: managing from someone else’s playbook instead of building their own.
Those first 90 days are one of the most consequential periods in any manager’s career. The foundations laid in that time, the relationships established, the habits formed, the credibility built or lost, shape everything that follows. Getting them right gives a new manager a platform to build from. Getting them wrong can create problems that take years to undo.
This post covers the mistakes that show up most consistently across those first 90 days, and what to do instead.
Key Points:
Becoming a manager for the first time is not a natural continuation of being a high performer. It is a fundamentally different job. The skills that get someone promoted, individual output, technical expertise, personal results, are not the skills that make someone an effective manager. The transition requires a shift in how someone defines their own success, from what they personally deliver to what they enable others to deliver.
Many new managers struggle with this shift for longer than they expect to. The instinct to do the work yourself, especially when you know you could do it well, does not go away overnight. Letting go of that instinct is one of the harder personal adjustments that comes with the role.
Not everyone who gets promoted into management is suited to it, and more importantly, not everyone who gets promoted wants to do it. Some people are promoted because they were the best at their previous role, and the assumption is made that management is the natural next step. Sometimes it is. Sometimes it is the wrong move entirely. What makes a good manager is a question worth sitting with before stepping into the role, not after.
Before the first 90 days can go well, the person stepping into the role needs to be honest with themselves about whether they genuinely want to manage people. Managing people well is hard work. It requires patience, emotional intelligence, an appetite for difficult conversations, and a willingness to make your success contingent on other people. None of those things are given. If someone would rather be doing the technical work than developing the people doing it, that is important to know early.
This is not a question about capability. It is a question about fit. Some of the best individual contributors make excellent managers with the right support. Some do not, not because they lack ability, but because management is simply not where their motivation lies. The first 90 days are the right time to reflect on this honestly, while there is still time to shape the role before it takes full shape around you.
The managers a new manager learns from have an enormous influence on the kind of manager they become. If the primary reference point is a manager who micromanaged, who avoided difficult conversations, who took credit for the team’s work or who played favourites, those patterns tend to get repeated even when the person involved genuinely intends to do things differently. Awareness of your influences is the first step to choosing which ones to follow. 10 first time manager tips is worth reading early in the role, specifically because it challenges some of the instincts that come from having been managed badly.
The best new managers actively seek out peers and mentors who are doing the job well and pay attention to the specifics. Not just what they do, but why. Not just the outcomes, but the thinking behind them. Learning to manage from observation and reflection rather than assumption is one of the habits that separates managers who keep developing from those who plateau early.
One of the things that takes many new managers by surprise is how much their relationships change the moment they become the manager. Someone who was a peer, a friend, a teammate, is now in a position of authority over those same people. That shift is real and unavoidable, and it needs to be navigated thoughtfully.
The two most common problems sit at opposite ends of the same spectrum. Some new managers try to keep things exactly as they were, treating their team as friends and avoiding anything that might create distance or awkwardness. Others overcorrect and become noticeably more formal, distant or authoritative in a way that feels sudden and off-putting to people who knew them before.
Both create problems. A manager who cannot make a difficult decision about a friend because of the relationship is not managing. One who distances themselves so completely that trust is lost is not managing either. The team needs someone who can hold both things: the relationship and the accountability. Manager empowerment is partly about developing the confidence to hold both at the same time.
New managers who were promoted from within the team also have to navigate the reality that not everyone will be happy about it. A colleague who also wanted the promotion. Someone who thinks they could do the job better. These dynamics do not disappear on day one. They just go underground, and a manager who pretends not to notice them tends to find out about them later in a more difficult way.
Have the conversation directly and early. If you know there is a team member who is finding the transition difficult, do not wait for it to surface on its own. A one-to-one that acknowledges the change in the relationship, without over-explaining or apologising for it, sets a tone of honesty that most people respond well to.
Set expectations clearly but conversationally. What does the working relationship look like now? What stays the same and what changes? A new manager who is clear about this early gives their team something to calibrate to. One who is vague about it leaves people to work it out for themselves, and they will all work it out differently.
Resist the temptation to bond with some of the team at the expense of others. Picking up where old friendships left off and visibly spending more time with certain team members signals a favouritism that undermines authority quickly. Even if the relationships are entirely appropriate, perception matters. Build relationships with everyone on the team from the start.
Everyone who has ever had a bad manager knows exactly what bad management looks like. Micromanaging. Avoiding hard conversations. Taking credit for wins and distributing blame for losses. Being inconsistent. Making decisions based on who you like rather than what is right. The list is long.
The uncomfortable truth is that people often replicate the management behaviours they experienced, even when they hated them. It is not deliberate. It is pattern matching. Under pressure, in unfamiliar situations, without a clear alternative model to draw on, new managers often reach for what they know.
A new manager who was micromanaged might find themselves over-checking work without realising they are doing it. One whose manager was conflict-avoidant might find themselves delaying difficult conversations because it feels too risky. These behaviours feel self-protective in the moment. They erode team performance over time.
Developing self-awareness is the most reliable protection against repeating poor management habits. Ask yourself regularly: what did I just do there, and why? Is that how I want to manage? Structured management development, like the 4 essential management skills new managers need, provides frameworks that give new managers something deliberate to reach for instead of defaulting to habit.
Seek feedback early and take it seriously. A team that sees their manager asking for honest input and doing something with it develops trust quickly. One that never gets asked, or that raises issues and sees them ignored, disengages just as fast. Asking “what do you need more of from me, and what do you need less of?” is a powerful and underused question in early one-to-ones.
New managers often feel pressure to demonstrate their value quickly by making changes. This instinct is understandable. They want to show that they see what is not working and that they have the confidence to fix it. But moving too fast on change in the first 90 days is one of the most reliable ways to lose a team before you have had a chance to build one.
Changes made before a new manager fully understands the team’s context, history, and dynamics often solve the wrong problems. A process that looks inefficient from the outside may exist because someone tried the obvious alternative years ago and it did not work. A team norm that looks unnecessary may be providing something important that is not immediately visible.
Teams also read early change as a signal about the kind of manager someone is going to be. A new manager who comes in and immediately starts changing things is often read as dismissive of what came before. Even if some of what came before needed changing, doing it before earning trust makes the change feel like an imposition rather than an improvement.
The first 90 days are better spent listening than changing. Have individual conversations with every member of the team. Ask what is working, what is frustrating, what they would change if they could. You will learn more from those conversations than from any amount of observation.
Separate what needs to change urgently from what can wait. Part of making that call well is understanding the difference between leadership and management. A new manager who is clear on which role they are playing in a given moment makes better decisions about when to act and when to wait. Some things genuinely cannot wait. A process that is actively causing problems, a team dynamic that is damaging, a gap in accountability that is affecting output. Those need addressing regardless of how long someone has been in the role. Everything else can be evaluated over a reasonable period before any changes are made.
When you do make changes, explain the reasoning. A team that understands why something is changing is far more likely to support it than one that is simply told what is different now. That transparency, even when the reasoning is imperfect, builds more goodwill than any polished change management communication.
Understanding how individual team members prefer to communicate, receive feedback, and work under pressure is one of the most practical things a new manager can do early in the role. Without that understanding, every interaction is essentially a guess.
New managers often manage everyone the same way, with the same communication style, the same level of detail, the same approach to feedback. Some team members respond well to that approach. Others do not, and when they disengage or perform below their capability, the manager often puts it down to attitude or motivation without recognising the mismatch.
A highly direct manager who communicates in bullet points and expects concise updates will struggle to build a relationship with a team member who needs context, reassurance, and a more conversational approach. Neither is wrong. The approach that does not adapt to the person is.
A DISC assessment gives both the manager and each team member a shared language for talking about working styles. Completing DISC assessments early in a new management role gives you a map of the team’s communication preferences before those preferences create friction you have to manage reactively. It also signals to the team that you are interested in how they work best, which is a good signal to send in the first 30 days.
Use the outputs in your one-to-ones. Not as a label to apply to people, but as a starting point for a real conversation about how someone prefers to be managed. What kind of feedback lands best for them? How much autonomy do they want versus how much check-in do they need? These are questions worth asking regardless of what any assessment says, but having a framework makes the conversation easier to open.
A team that does not know what matters most will fill that gap with their own assumptions, and those assumptions will not all point in the same direction. Unclear priorities are one of the most consistent sources of friction in the first 90 days, and they are almost entirely avoidable.
New managers are often clear on priorities in their own heads but have not communicated them explicitly to the team. Conversations happen one at a time in one-to-ones, not everyone hears the same message, and the team ends up working to different interpretations of what the manager wants. Some team members will prioritise what they have always prioritised. Others will try to second-guess the new manager’s preferences. Neither is optimal.
Conflicting priorities also create stress. A team member who receives equal urgency signals on three different pieces of work from their manager will either try to do all three simultaneously and do none of them well, or will pick one and hope they picked the right one. Either outcome is avoidable.
Be explicit. Tell the team what the priorities are, in what order, and why. Do this in a group setting so everyone hears the same message at the same time. Then make it easy to reference. A shared document, a team meeting agenda item, a regular check-in where priorities are reviewed. Clarity is not a one-time act. It is a habit.
When new priorities emerge, say so. If something that was a priority last week has dropped down the list, the team needs to know. Nothing creates confusion faster than a manager who changes direction without announcing it, leaving the team to find out by looking at what is getting attention and what is being ignored.
New managers often take on too much because they have not yet learned to fully delegate, because they do not yet trust the team to deliver, or because they are still trying to demonstrate value through personal output rather than team output. Whatever the reason, the effect is the same. The manager becomes a bottleneck, the team becomes dependent, and neither thrives.
The immediate problem is workload. A manager who is still operating as an individual contributor as well as trying to manage a team is doing two jobs badly rather than one job well. The medium-term problem is what it communicates to the team. If the manager is involved in everything, it signals either that they do not trust the team or that the team has not been set up to work without that involvement. Both create dependency rather than capability.
There is also a credibility issue. A manager who cannot let go of the tasks they used to do is still positioning themselves as a doer rather than a leader. Teams notice this, and it makes it harder for them to see the manager as someone who is developing them rather than competing with them.
Delegation is a skill that requires practice, and it starts with accepting that someone else may do a task differently to how you would do it, and that differently does not automatically mean worse. Set clear expectations on outcomes rather than methods, and resist the urge to step back in the moment something is not going exactly as you would have done it.
Map your time deliberately. What are the things that only the manager can do? Leading one-to-ones. Making decisions that require management authority. Representing the team to senior leadership. Those are management tasks. Everything else is potentially delegatable. A clear picture of where your time is going is the starting point for working out where it should be going instead. A management training programme template can help turn that picture into a structured plan, so the shift from doing to leading becomes deliberate rather than accidental.
A new manager’s diary can fill up very fast, often before they have had a chance to assess whether every meeting in it is a good use of their time. Attending everything feels safe. It feels thorough. It is usually neither.
Sitting in every meeting has two problems. The first is the obvious one: time. A manager who is in back-to-back meetings has no time to think, to develop relationships with the team, to work on anything proactively, or to simply be available. The second is what it signals to the team. A manager who turns up to every team meeting without delegating the running of any of them is telling the team that they cannot be trusted to run things themselves.
New managers are also often invited to more meetings than they should attend, because they are new and people want to include them. Not every meeting is asking for their input. Some are asking for their presence to be signed off on decisions that do not need signing off. Learning to read the purpose of a meeting and the real reason for being there is a skill that takes time to develop but pays back significantly once it does.
Audit the diary with fresh eyes after the first month. For every recurring meeting: does this need a manager? Does it need this manager? What would happen if you were not there? If the honest answer is that nothing much would change, that is worth knowing. A solid development plan for managers helps clarify where time is actually best spent.
Develop team members to lead. Running a team meeting, facilitating a project update, presenting to stakeholders. These are all development opportunities that a new manager can create by stepping back. The team grows. The manager gets time back. The workload distributes more evenly. None of that happens if the manager attends everything.
Most organisations have more tools available to managers than they are fully using. Project management platforms, performance tracking systems, communication tools, data dashboards. New managers who do not invest time in understanding what is available often end up managing by instinct and memory when they could be managing with real information.
The most common problem is not using what is already there. A new manager who relies on informal conversations and gut feel to assess team performance is working with incomplete information. They will miss things. They will be slow to spot problems. They will find it hard to demonstrate progress or challenges when speaking to their own manager, because they have nothing to point to.
There is also the team visibility issue. If a manager does not know what everyone is working on or where each piece of work stands, they cannot prioritise effectively, cannot allocate resources intelligently, and cannot support someone who is struggling until the problem has already grown.
Spend time in the first two weeks understanding what tools the team already uses and how well they are being used. Talk to the team about what works and what does not. You will often find that the tools are there but either underused or used inconsistently, and that a small amount of structure around their use would make a significant difference.
Resist the temptation to bring in new tools before you understand the existing ones. Every tool change comes with a learning curve and a transition cost. A new manager who arrives and immediately replaces what the team uses signals impatience and a lack of interest in understanding what was there before. Improve what exists first. Introduce new tools only when there is a clear case for them.
Teams run on processes, and processes only work when the people who are supposed to follow them follow them. A new manager who lets process compliance slip in the first 90 days because they are focused on relationships and settling in creates a consistency problem that is harder to address the longer it runs.
The most common scenario is a new manager who inherits a team where certain processes have gradually been allowed to slide. Reporting that does not get done on time. Approval steps that get bypassed. Standards that everyone knows exist but that nobody has been held to recently. A new manager who wants to be liked sometimes chooses not to push on these things early. The problem is that once the pattern is established, it becomes the new default.
There is also the opposite problem: a new manager who enforces processes rigidly without understanding the context behind them. Some processes exist for very good reasons that are not immediately obvious. Others have been superseded by something better but have not been formally updated. Enforcing the latter creates friction without any benefit.
Take the time to understand the processes that exist, why they exist, and whether they are currently being followed. Where there are gaps, address them directly but not punitively. A conversation that explains why the process matters and what happens when it is not followed is more effective than enforcement for its own sake.
Where processes are not fit for purpose, the right move is to change them through the proper channel rather than allow informal workarounds to become the norm. Flag it, get the appropriate sign-off, update the process, and communicate the change. That approach builds more credibility than either blind enforcement or silent tolerance of non-compliance.
A new manager who focuses on tasks rather than people will get short-term compliance but will not build a high-performing team. Tasks get done. People grow, develop, and make decisions. The manager’s job is the people, not the to-do list.
Task-focused management shows up as an obsession with outputs over outcomes, with activity over impact, and with tracking what is being done rather than understanding how people are doing. It produces a team that follows instructions but does not take initiative, that reports upwards rather than thinking independently, and that only performs when the manager is paying close attention.
It also exhausts the manager. Managing tasks requires constant involvement. Every decision comes back to the manager. Every problem needs the manager to solve it. The team becomes unable to function without close direction, because close direction is all it has ever been given.
Shift the one-to-one conversation from status update to development. Instead of asking “where are things with the Smith account?”, ask “what is the biggest challenge you are working through this week and what options are you considering?” The first manages the task. The second develops the person. The GROW coaching model gives you a simple four-step structure for having that kind of conversation every week.
The most common failure mode in new managers is not strategic. It is interpersonal. Specifically, the habit of avoiding conversations that feel uncomfortable. A team member who is underperforming but has not been told. A behaviour that is affecting the team but that has not been addressed. A conflict between two people that the manager noticed but stepped around.
Conflict avoidance feels protective in the short term. The difficult conversation does not happen, the immediate discomfort is avoided, and nothing changes visibly. The medium-term reality is that the problem grows. The underperforming team member now has a longer pattern to address. The behaviour that was not challenged has become the norm. The conflict that was not mediated has spread.
There is also a credibility cost. Teams notice when a manager avoids difficult situations. They lose confidence in the manager’s ability to handle the hard parts of the job. The people who are performing well start to question why it is acceptable for someone else not to be. The team’s trust in the manager’s fairness and competence erodes.
The reframe that helps most is this: a difficult conversation held early is almost always easier than the same conversation held later. The longer a problem is left, the more entrenched it becomes, the more evidence accumulates on both sides, and the higher the emotional stakes for everyone involved. Difficult conversations feature heavily in the core topics of leadership training for good reason and they are one of the clearest separators between managers who build strong teams and those who do not.
Prepare before you go in. Know what you want to say, what outcome you are looking for, and what you will do if the conversation does not go the way you hope. Having a clear sense of those three things before a difficult conversation reduces the anxiety significantly and makes it much more likely to go well.
Practice helps more than most managers admit. Role-playing a difficult conversation with a trusted colleague or mentor before having it for real is not a weakness. It is preparation. The words matter. How you open matters. Whether you lead with facts or feelings matters. Getting those things right in a safe environment makes the real conversation considerably less difficult.
The first 90 days as a manager are a learning curve that everyone goes through, and having the right support behind you makes a significant difference to how it goes. MTD’s Essential Management Skills programme is designed specifically to give new and developing managers the practical tools, frameworks, and confidence they need to lead their teams effectively from the start.
Have a look at what is available and find the right management development programme for you or your organisation.
Written by Sean McPheat
CEO of MTD Training and Amazon bestselling author. Sean writes about leadership, business, and personal growth, drawing on 20+ years of experience helping over 9,000 companies improve performance.
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Updated on: 20 October, 2026
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