also get there EARLY to check out the track and talk to the people running it to get any details you might miss.
when you get there ask around, tell them its your first time out and are looking for some advice, whats a good range of gearing to run on this track, what turns should I look out for, should I soften up the suspension or make it hard, etc etc.

during the race, dont try to win, try to get your lap times consistent. try to figure out how hard to hit what turn and were the brakeing zones are, use this oportunity to learn the track.

dont expect to place good the first time out, just use this opportunity to learn what running on a course with traffic is like.

and most imortantly!!!!!! have fun.