If you can find some copies of Supercross races from the last couple of years, slow it down and watch Jeremy McGrath. His body positioning is awesome, and I feel I've learned a lot just watching him. You'll notice he's always up on the tank when seated, or his head is always up over the triple clamps when he's standing.
A lot of guys are rotating their bars forward to force themselves into this attack position. Also, look at their elbows- always up. Since I mostly trail ride, I get lazy on the smoothe sections and drop my elbows, but it's funny tha whenever the going gets rough my elbows always pop up now just out of habit, and it's really amazing how much more control you have.:cool:
When you ride, you want to always have your elbows up. When you stand, keep your gripped with the gas tank, have your head just past the handlbars. You should never look at your fender, look at the corner when you have to go. Look at the destination, pin it, brakes, pin it......do this for the whole race, you will definetly have a better race.