As an individual contributor, your primary method of adding value to your organization is the quality and quantity of your work. Your ability to work as a team member and support others is a great bonus, but most companies will keep a highly talented, productive worker even if he/she doesn’t have great communication skills or any leadership potential. As a manager you are valued for something completely different.
In a leadership role, your primary currency with your reports, your supervisors and your customers is your word. If you commit to getting something done to any of these constituencies, it must get done or you will lose the credibility that is fundamental to your success. Many new managers slip into the bad habit of over-committing. They promise too much, set unrealistic deadlines, and fail to properly plan for obstacles and contingencies.
To succeed in the early months after your promotion, make sure you are mindful of any commitments you make. Keep careful track of deadlines, and if you are asked to estimate the time required to complete a project, ask for time to put together a full analysis before you commit to a timeline. As you refine your knowledge of your team and their capabilities, you can start to make off the cuff estimates, but when you are just getting started it’s far better not to guess.