Politics and projects go hand in hand. Team conflict, competing agendas, stakeholder dysfunction, resource constraints, and a myriad of other challenges exist and will send your project careening out of control if not managed properly.
Learn to negotiate from a position of strength
Do everything you can to educate those around you about Project Management. Stress the benefits and overcome the objections by pointing to your successes.
Master the art of influence.
An effective executive sponsor can help minimize political time wasting events that slow project progress and increase project budgets.
Recognize that conflict on your project is inevitable and necessary. How you respond to conflict will determine how successful you are.
Mastering the art of negotiation is a critical skill for project managers.
Realize that for the most part internal politics wastes time and is usually not something that people enjoy.
Team commitment and loyalty will help to minimize project politics.
Don't fight a political system you don't understand and can't influence. Leave that to the experts. (Hint: get these experts to support your project if possible).
A good communications plan will help to lessen the politics on your project.
Every project usually has at least one "politician" in the organization that is out to either sabotage it, or will try to ensure that it isn't fully implemented.
Recognize that change (which is what projects are all about) scares some people and your project's deliverables can lead to a loss of power or influence for certain individuals or departments. Anticipate this and have a plan to deal with the behaviors that will surface.