Starting a new job comes with pressure, expectations, and one silent fear making mistakes in your first 90 days.
Those first three months are critical. They shape how your manager sees you, how your colleagues treat you, and whether you are trusted with bigger responsibilities.
The truth is simple:
Most candidates don’t fail because they lack skills. They fail because of avoidable mistakes.
If you understand these mistakes early, you gain a serious advantage.
Let’s break it down.
Why Your First 90 Days Matter More Than You Think
Your first 90 days are not just about learning the job.
They are about:
- Building trust
- Proving reliability
- Understanding workplace culture
- Showing initiative without overstepping
In cities like Lagos, where workplaces move fast and expectations are high, employers often decide your long-term value within weeks.
You are being observed not judged harshly, but evaluated quietly.
Top Mistakes Candidates Make in Their First 90 Days
1. Trying to Impress Instead of Learning
This is the most common mistake.
New employees often feel the need to prove themselves immediately. So they:
- Talk too much in meetings
- Suggest changes too early
- Try to “fix” things they don’t fully understand
Why It Backfires
You may come across as:
- Arrogant
- Impatient
- Disrespectful of existing systems
What to Do Instead
Focus on:
- Listening more than speaking
- Asking smart questions
- Understanding before suggesting
Think of your first 30 days as research, not performance.
2. Not Asking Questions
Some people stay quiet because they don’t want to look inexperienced.
Big mistake.
Why It Hurts You
Managers don’t expect you to know everything.
But they do expect you to:
- Ask questions
- Clarify expectations
- Avoid repeated mistakes
Silence is often interpreted as:
- Lack of interest
- Lack of initiative
Smart Approach
Ask:
- “What does success look like in this role?”
- “How do you prefer updates?”
- “What should I prioritize this week?”
3. Ignoring Workplace Culture
Every company has an unwritten rulebook. In Nigeria, especially in Lagos corporate spaces:
- Communication styles vary
- Hierarchy matters
- Timing and tone matter
Common Mistakes
- Being too casual too early
- Misreading authority levels
- Overstepping boundaries
What to Do
Observe:
- How people communicate
- How decisions are made
- Who influences what
Adapt before you act.
4. Overpromising and Underperforming
You want to impress, so you say “yes” to everything.
Then reality hits.
Deadlines slip. Quality drops.
Why This Is Dangerous
Trust is fragile in your first 90 days.
One missed expectation can:
- Reduce confidence in you
- Limit future opportunities
Better Strategy
- Set realistic expectations
- Communicate early if delays happen
- Deliver consistently, not occasionally
5. Not Building Relationships
Some people focus only on tasks. They ignore people.
That’s a mistake.
Why Relationships Matter
Your success is not just about what you know.
It is about:
- Who supports you
- Who shares information with you
- Who trusts you
What to Do
- Introduce yourself properly
- Be approachable
- Engage in small conversations
- Respect everyone from interns to senior staff
6. Avoiding Feedback
Many new employees fear criticism. So they avoid feedback.
Reality Check, Feedback is not an attack. It is guidance.
What Happens When You Avoid It
- You repeat mistakes
- You grow slowly
- You miss expectations
Smart Move
Ask:
- “How am I doing so far?”
- “Is there anything I should improve?”
This shows maturity.
7. Acting Like You Already Know Everything
Confidence is good. Overconfidence is dangerous.
Signs of This Mistake
- Interrupting others
- Rejecting suggestions
- Ignoring instructions
What Managers Think
- “This person is difficult to manage”
- “They may not be coachable”
Better Approach:
- Stay confident but open.
- Be willing to learn.
8. Poor Time Management
Your first 90 days come with:
- Training
- Tasks
- Meetings
- Adjustments
Without structure, things pile up.
Common Issues
- Missing deadlines
- Forgetting tasks
- Feeling overwhelmed
Fix It
- Use a to-do list
- Prioritize daily
- Break tasks into smaller steps
Consistency beats speed.
9. Not Understanding Your Role Clearly
Some employees start working without full clarity.
They assume instead of confirming.
Result
- Doing the wrong tasks
- Misaligned expectations
- Wasted effort
What to Do
Clarify:
- Your responsibilities
- Key performance indicators (KPIs)
- Reporting structure
10. Staying Invisible
- Trying not to make mistakes, some people become too quiet.
- They do their work but stay unnoticed.
Why This Is a Problem
If people don’t see your value, they won’t recognize it.
What to Do
- Share updates
- Speak when necessary
- Participate in discussions
Visibility builds credibility.
The Psychology Behind These Mistakes
Most of these mistakes come from:
- Fear of failure
- Pressure to impress
- Lack of confidence
- Overcompensation
Understanding this helps you stay balanced.
You don’t need to be perfect.
You need to be:
- Consistent
- Willing to learn
- Easy to work with
What Employers Actually Expect in Your First 90 Days
Let’s be clear.
Employers are not expecting perfection.
They are looking for:
- Willingness to learn
- Reliability
- Good communication
- Positive attitude
- Adaptability
If you deliver these, you are already ahead of many candidates.
Simple 30-60-90 Day Strategy
First 30 Days
- Learn everything
- Ask questions
- Observe culture
Next 30 Days (60 Days Total)
- Start contributing
- Build relationships
- Take small responsibilities
Final 30 Days (90 Days)
- Deliver results
- Show initiative
- Prove reliability
Frequently Asked Questions
What are the biggest mistakes in the first 90 days of a job?
- Trying to impress too quickly, not asking questions, ignoring workplace culture, and overpromising are the most common mistakes.
How can I succeed in my first 90 days?
- Focus on learning, communication, consistency, and building relationships.
Is it normal to make mistakes in a new job?
- Yes. What matters is how quickly you learn and improve.
Should I speak up in my first month?
- Yes, but thoughtfully. Ask questions and contribute when relevant.