1st make sure the car is sound, no knackered bushes, ball joints etc... make sure the battery is well fitted and the seat belts etc are sound.
Make sure you have a decent oil in and its filled up to the max line, a decent oil will be a fully syth and preferably 15w50 or similar as I doubt you have an oil cooler. Generally you get what you pay for with oil..
Disks/Pads/Tyres, just make sure they have plenty of meat in them as you will probably to 10-20 times the wear on track, i.e. 200 miles on track could easily equate to 2000-4000 road miles. This also goes for just about all moving components.
On the day take a big sports bag to remove every thing from the car & I mean everything that isnt bolted down.
Check tyre pressures, take a gauge and a foot pump. Also make sure you take your drivers license, both bits as you probably wont be allowed on without them.
Dont bother with expernsive upgrades day one, but when you do upgrade only try to do it once dont go for something a little better but listen to what is recommened by those who know and take the advise..
Finally, leave your ego at home, take it easy, take instruction, move out of the way of others who are faster and just enjoy
