Since it is your first time I won't get into car prep except that you should pump your tires up a few pounds above their normal settings to keep the tread flat on the ground when the side wall tries to lift them from the cornering forces.
The main thing, again I won't go into too much depth here either, is to walk the course a lot until you are absolutly positive where to go, I like to walk it until I can go sit in my car, close my eyes and visualize going through the whole course.
If you can, get a few rides with others who are more experienced to see what they do and also to help you to know where the layout of the course. On that note, find out who are the better drivers, go talk to them as most are very willing to help the new guy and watch them out on the course to see how they are doing things if you can't talk them into a ride along.
There should be someone who walks the course with the Novice group who will get a lot of your concerns answered and who can answer any other questions you may have Don't be afarid to ask questions either to him or any of the other competitors, most all are eager to help you get going.
Once you get your first event under your belt you will be more prepared for the next one and then can start getting into working on your driving technique/skills, changing around tire pressures to effect over/under steer, what mods you are going to do to get your car more competitve, etc.
In the future, if you can't do so before the event, install a
panhard bar to prevent tire rub as the axle will shift lateraly when hard cornering forces are applied without one and will cause tire rub if you have close clearances.
Most of all, have FUN!!
let me hear some experiences and tips. thanks guys
. I say take it easy on your first runs and learn the track like that...its not like you have to push all out on the first run. 
