In reply to herman0055: I'd say from experience that the best thing is just making sure everything is right for you, so you feel as comfortable and confident as possible when you're up to climb.
That means making sure you've packed everything the day before, with good food and energy drinks, money if you want to but anything. You've got your favourite boots on, your chalk bag is full, your wearing your lucky top etc.
Then on the day get really well warmed up, familiarise yourself with your routes, make sure everything will go smoothly, and that way you can't have any doubts.
Lastly, just remind yourself that, at the end of the day, it really doesn't matter how you do, so long as you're enjoying your climbing.