You can never be the best forever. One may be be the best for now but that will never last. You can only do your best. If you've done your best then you can't do anymore. What I've found helps is don't give a $h!T how you do. Don't expect yourself to be better than the other guy. If you are better than the other guy or if you finish well great but don't have those expectations of yourself. The nervousness for me was me letting myself down. Nervousness for me was performance anxiety. I was nervous that I was was not going finishing as well as I expected myself to finish or letting other drivers that I thought wasn't as good as me finish infront of me. If this doesn't work then imagine all the guys around you on the driver stand are wearing dressess and you're the only cool one there.