Getting into Microsoft can be hard. Make sure you are thoroughly prepared and have done a lot of research.
Sadly, the parts of Microsoft I saw have a lot of politics. Tread carefully, and ask others more experienced than you for advice.
Teams or groups tend to work on overlapping tasks, therefore you have to fight for your patch and, sometimes, it isn't about getting the job done right, it's about getting it done first, and publicizing that fact.
Because teams are graded on a curve - 10% lowest performaners, 70% in the middle and 20% high performers, you are effectively competing against your own team throughout the year. Make sure all the managers in your group - not just your own - know about your achievements.
Reorganizations and restructuring are the order of the day at Microsoft. Learn to go with the flow as the change happens and create a new niche for yourself when the dust settles.