Leadership & Management

New manager: succeed in 90 days

- A structured 90-day plan broken into 3 phases (Days 1-30, 31-60, 61-90)

Fionnuala O'Driscoll
10 min read
leadershiponboarding managermanagement

What you'll learn

  • A structured 90-day plan broken into 3 phases (Days 1-30, 31-60, 61-90)
  • Concrete actions for each week
  • The 5 fatal mistakes new managers make
  • A comprehensive 90-day checklist

Phase 1: Days 1-30 — Observe, Listen, Understand

A new manager's natural instinct is to prove their worth by acting fast. You need to do the exact opposite. Your first month should be dedicated to listening and observing. You don't yet understand the invisible dynamics of your team, and acting without that understanding is navigating blind.

Key principle: listen 80% of the time, speak 20%.

Week 1: Meet every team member one-on-one

Schedule a 30-minute individual meeting with each person on your team. Not in a sterile conference room — find somewhere relaxed. Your goal isn't to present your vision, but to listen.

Ask these four questions:

  1. What's working well on the team right now? — You identify what not to break.
  2. What frustrates you on a daily basis? — You spot recurring pain points.
  3. If you could change one thing, what would it be? — You prioritize expectations.
  4. What do you need from me? — You show that you're here to serve, not to control.

Take detailed notes. The patterns that emerge from these conversations are pure gold.

Week 2: Map the ecosystem

Your team doesn't operate in a vacuum. Identify:

  • Key stakeholders: who are your internal contacts, your team's clients, the people who control resources?
  • Dependencies: which teams do you depend on? Who depends on you?
  • Team dynamics: who are the informal leaders? Where are the alliances and tensions?
  • Unwritten rules: every team has its habits, taboos, and unspoken rituals. Identify them before you disrupt them.

Make no promises during this phase. Simply say: "I'm taking the time to understand before I act."

Week 3: Understand the work from the inside

Attend your team's meetings as an observer. Shadow a team member for half a day. Use the tools your team uses. Read existing documentation.

The goal isn't to become an expert in every role, but to understand:

  • The actual workflow (not the official process document)
  • Bottlenecks
  • Daily frustrations with tools and processes
  • Each person's workload

Week 4: Synthesize and share your observations

By the end of the first month, you have a wealth of information. Synthesize it into three categories:

  • Quick wins: easy-to-solve problems with immediate impact
  • Deep pain points: structural issues that require careful thought
  • Landmines: sensitive topics that must be handled delicately

Share your observations with the team — not your solutions. Say: "Here's what I've observed and heard. Does this match your reality?" This validation builds trust and corrects your blind spots.


Phase 2: Days 31-60 — Establish Credibility

You've listened. Now it's time to act — but in a targeted and deliberate way.

Key principle: earn authority through competence and care, not through your title.

Set up rituals

Rituals create predictability, and predictability creates trust. Establish three regular touchpoints:

  1. Weekly team meeting (30 min): structured agenda — progress, blockers, priorities for the week. Not a manager monologue, but a collective exchange.
  2. Weekly one-on-one with each direct report (30 min): it's their agenda, not yours. Let them choose the topics. Your role is to unblock, coach, and support.
  3. Bi-weekly retrospective (45 min): what went well? What can we improve? What concrete actions do we commit to?

Deliver quick wins

Take the 2-3 most frequently mentioned pain points from your initial conversations and solve them. These are often simple things:

  • An unnecessary bureaucratic process to eliminate
  • A missing tool to provide
  • A recurring meeting with no value to cancel
  • Hard-to-access information to make available

Quick wins build trust faster than any strategic speech. They prove you listened and that you act on what you hear.

Communicate your management style

Don't let your team guess how you operate. Be explicit:

  • How you make decisions: collaborative, consultative, directive depending on context?
  • How you give feedback: how often? In what form?
  • What you expect: autonomy with regular check-ins? Proactive updates? Right to fail?
  • Your non-negotiable values: transparency, commitment to deadlines, mutual support?

This "manager user manual" prevents misunderstandings and toxic assumptions.

Start giving feedback

Use the SBI model (Situation — Behavior — Impact):

  • Situation: "During Tuesday's client meeting..."
  • Behavior: "...you presented the results with very clear visuals and addressed every objection..."
  • Impact: "...the client approved the project immediately. That was outstanding."

Golden rule: give positive feedback publicly, constructive feedback privately. And never stockpile feedback — deliver it within 48 hours.


Phase 3: Days 61-90 — Vision and Structure

You've observed. You've built trust. Now it's time to provide structure and direction.

Key principle: your job is no longer to do the work — it's to enable others to do their best work.

Set clear objectives

Every team member should be able to answer this question: "What are my top 3 priorities this quarter?" If they can't, you have an alignment problem.

  • Align team goals with company strategy
  • Use a framework like OKRs (Objectives and Key Results) to add structure
  • Make sure each person understands the "why" behind their objectives
  • Make goals visible and measurable

Implement structured feedback

Beyond informal daily feedback, establish a formal framework:

  • 360° feedback for individual development
  • Peer feedback among colleagues to strengthen collaboration
  • Self-assessment to develop each person's reflective capacity

Structured feedback transforms individual development from an annual event into a continuous process.

Delegate strategically

Delegation is a manager's most powerful — and most underused — lever. For every task, ask yourself: "Am I the only person who can do this?"

  • Identify each team member's strengths and assign accordingly
  • Give autonomy with accountability: delegate the outcome, not the method
  • Resist the urge to micromanage: if you delegate, trust
  • Accept that the result may differ from what you would have done — different doesn't mean inferior

Have the hard conversations

During your first 60 days, you've observed problems: underperformance, interpersonal conflicts, role ambiguity. It's time to address them.

Hard conversations don't get easier with time — they get harder. Every week of silence reinforces the problem.

To approach a difficult conversation:

  1. Prepare the facts (not your interpretations)
  2. Choose the right time and place (never in public, never in the heat of the moment)
  3. Start with the observed impact, not with an accusation
  4. Listen to the other person's perspective
  5. End with a concrete action plan and clear deadlines

The 5 fatal mistakes of new managers

1. Trying to change everything in week one

You have brilliant ideas. You see inefficiencies everywhere. Resist. Changing things too quickly sends a devastating message: "Everything you did before me was worthless." You build resistance instead of trust. Observe first. Understand why things are the way they are. Then change them.

2. Trying to be everyone's friend

You need trust, not friendship. Being liked and being respected are two different things — and sometimes contradictory ones. A manager who wants to be liked avoids unpopular decisions, postpones hard conversations, and ends up losing the team's respect.

3. Not delegating

"It's faster if I do it myself." This sentence is the new manager's poison. Every task you keep for yourself is a task your team doesn't learn to do. You become a bottleneck instead of a force multiplier.

4. Avoiding hard conversations

Feedback delayed by 3 months is 10 times harder to deliver than feedback given within 48 hours. The problem doesn't disappear when you ignore it — it grows. Managers who avoid confrontation create dysfunctional teams where problems accumulate beneath the surface.

5. Copying your previous manager

Your context is different. Your team is different. Your personality is different. What worked for your previous manager won't necessarily work for you. Take inspiration, absolutely. But develop your own authentic style.


The 90-day checklist

Phase 1 — Days 1-30: Observe and listen

ActionDone?
Schedule a 30-min one-on-one with every team member
Ask the 4 key questions in each meeting
Take detailed notes and identify patterns
Identify key stakeholders and meet them
Map cross-team dependencies
Identify informal leaders and team dynamics
Spot the team's unwritten rules
Attend meetings as an active observer
Shadow a team member for half a day
Test the team's tools and processes
List quick wins, pain points, and landmines
Share your observations (not solutions) with the team

Phase 2 — Days 31-60: Build credibility

ActionDone?
Establish the weekly team meeting (30 min)
Establish weekly one-on-ones with each team member
Establish the bi-weekly retrospective
Solve quick win #1
Solve quick win #2
Solve quick win #3
Write and share your "manager user manual"
Give at least one positive feedback per week to each team member
Deliver constructive feedback using the SBI model
Identify the team's training needs

Phase 3 — Days 61-90: Vision and structure

ActionDone?
Define OKRs or quarterly objectives with the team
Ensure each person knows their top 3 priorities
Align team objectives with company strategy
Implement a structured feedback process
Delegate at least 3 tasks you were doing yourself
Have at least one necessary difficult conversation
Create a development plan for each team member
Conduct a 90-day review with your own manager

Key takeaways

"Your first 90 days as a manager don't define your career — but they set the trajectory."

  • Month 1: observe and listen. The biggest mistake is acting without understanding. Invest in relationships before processes.
  • Month 2: act with precision. Quick wins and rituals build trust faster than grand speeches.
  • Month 3: structure and set direction. Clear objectives, regular feedback, and smart delegation are your three levers.
  • Develop your own style. Not your previous manager's, not the textbook's — yours, adapted to your context.
  • Never avoid hard conversations. It's uncomfortable. It's necessary. It's what separates a good manager from a mediocre one.

Practice your first difficult conversations

Theory is good. Practice is better. TrustLeader's interactive system simulations let you rehearse real management situations: difficult feedback, team conflicts, disengaged employees. No risk, with personalized feedback.

Start practicing for free


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