QUOTE(oboist @ Nov 23 2005, 10:23 PM)

Visualise yourself being amazingly successful and you'll be surprised how much that will help. Stand tall, breathe well (in all the places you've rehearsed) and smile at the audience before you start. That will give you and them confidence.
That's excellent advice.
Practise the whole performance routine before the day, maybe in front of a full length mirror (at least as scary as a large audience if you haven't done it before!). When you have finished your piece, however well you think you played it, smile at the audience again and bow. They are definitely going to clap, and your bow is a silent way to thank them for listening. Look at your knees, don't leave your head sticking up to look at the audience. Only after you have bowed pick up your music and go to wherever you need to go next. Be ready to act "I'm delighted to be doing this" however you feel on the night.
I wonder if you know the song from "The King and I" that starts "Whenever I feel afraid, I hold my head erect and whistle a happy tune, so no-one will suspect I'm afraid". There's a bit later on that goes "The result of this deception is very strange to tell, for while deceiving others I deceive myself as well". The quotations may not be exact because I haven't got the copy in front of me, but that's the general idea.
Best of luck, and I hope you will really enjoy playing.