I get nervous before big meetings.  I always have.  Presentations, important meetings, speeches, conversations.

My energy level skyrockets.  It is nervous energy.  Pacing energy.  I calm myself by organizing thoughts and thinking of possible questions and their answers.  I talk to myself, working through important points, shorthanding them on a card, creating a detailed agenda provides an important steam valve for all that energy.

In all my career I have never once walked into a meeting with the thought: "I've got this nailed."  The best results have always come from the kind of preparation which allows for those unexpected detours.  All of the important points are nailed down with supporting arguments and proofs and examples.

The nervousness never goes away but it keeps me thinking of ways to stem it.  It serves its purpose.