Pace yourself. It is a long race. Riding over your head will cause you to make unnecessary mistakes. It's kinda hard to do this at first, but as the race wears on, you'll have more energy and your machine will be in one piece. Hitting trees will cause you to spend more energy and time pulling it off the tree, than slowing down a hair to get through the area cleanly.
Speaking of machines. Check your ride over carefully for any problems that could crop up in the middle of the race. Is your air filter clean? New oil? Chain properly tightened? Axle nut properly tightened? Simple routine maintenance items will help you. If the wheeler isn't running then you can be the fastest guy out there and still be in dead last.
Also have fun with it. You're going to find out that it is alot of work and that there are guys that are alot faster than you. The race is 25% machine and 75% rider. But the machine has to be running properly. I just started racing this past summer and in only two races I have learned alot and had a blast. And that's what it is about. I'm no expert but these are areas that I have learned are important to cover. Good luck. Let us know how you did.
Ray
1999 400EX-99 Hetrick Racing 416 motor, FCR 39mm Carb, Hetrick Racing full exhaust, 2000 pc'd and gusseted frame, 450R shocks w/ GTT springs, Elka converted rear stock shock w/ GTT XC link, Hiper wheels w/ Holeshot XCT's, Graydon Nerfs and steering stabilizer, PRM Bumper and full skids, Wave rear rotor, TrailTech Computer, Sidewinder Ti-Moly Chain and Sprockets, Cycra handguards, +1 Steering stem and Protaper bars
07 DRR 70 Built by Hetrick Racing, w/Elka Shocks