Warm-up to get your body ready for the hard start and pre-ride to learn the course (do a slow lap and try to spot everything, then do a faster lap to see how the tricky spots are at a racing pace).

When you're pre-riding, watch the faster riders from the later races if they're out on the course as well. Don't worry about keeping with their pace, but look at the lines they take. Quite often the "racing line" worn into the course isn't the fastest line through tricky spots. In the last race I did I learned two different lines that were better than the ones I'd been taking just by watching other riders.