Bring it with you to the race. evaluate there. (it might be overkill but if it makes you more confident then wear it)
Practice sprinting out of the start. Make sure your heart rate is going a little bit before your start if you can.
Know where your skills are good and bad and use them accordingly.
Don't burn up all your energy in the fast sections only to be fatigued when the rockgardens/drops come.
Pre-ride/walk the course. observe the faster riders and their lines.
Lookup or inquire as to the last years timing if you're trying to be competitive. Practice the sections you know you'll have problems with. No sense in hammering and wasting energy in the sections you know how to do well already.
Set your tire pressure once you get there and stick with it.
Try to visualize the course as you're racing and what is comming up. It'll help picking faster lines and accelerating properly.
And have fun,