The first ninety days set a reputation that is expensive to change later. The goal is not to prove yourself immediately. It is to understand the system before attempting to improve it.
Spend the first thirty days learning and asking questions, the next thirty contributing visibly on something small and useful, and the final thirty proposing one improvement you can own. Book a conversation with your manager about expectations in week one and revisit it at day ninety.
Days 1 to 30: learn the system
Resist the urge to fix things immediately. Every organisation has reasons, sometimes bad ones, for how it operates, and the person who arrives redesigning processes in week two rarely gets a second hearing.
Ask three questions of as many colleagues as will spare fifteen minutes: What does this team do well? What frustrates you most? If you had my role, what would you look at first? Write down every answer, and note who says the same thing.
Days 31 to 60: contribute visibly
Find something small, genuinely useful and clearly attributable, and complete it well. A tidy piece of documentation, a report that saves someone an hour a week, a process everyone complains about but nobody owns. The size matters far less than the reliability signal it sends.
This is also the point to establish your working rhythm with your manager: how often you meet, in what format, and what they want to hear about without being asked.
Days 61 to 90: propose something you can own
By now you understand the constraints. Choose one improvement, ideally connected to something you heard repeatedly in your first month, and propose it with a clear scope, a rough timeline and a way to measure whether it worked. Ask to own it.
Manage upward deliberately
Most managers are stretched and will not chase you for information. A short weekly summary of what you finished, what is in progress and what you need from them takes ten minutes and disproportionately shapes how your contribution is perceived.
Position for the twelve month conversation
Keep a running record of what you delivered and what changed as a result, in specific terms. When the salary review arrives, the person with a documented list of outcomes has a conversation. The person relying on memory has a request.