Well, number 1 rule is to watch out for cones.
Seriously. Take it easy and have fun. Get a helmet, get there, lower tire pressure and get a feel of the lay of the land. Everyone is usually helpful to point you in the right directions for sign in and assignments and such. Do the track walk and hopefully they will have a “new driver’s” walk with an instructor. Figure out your lines and go over them in your head. Hopefully you will do corner work first, so you get a better idea how the track and cars go.
When it’s your time to run, Follow the instructions by the pit marshals and have fun. Ramp up incrementally. Make the first run at a comfortable pace. If you goof, oh well, it’s no big deal. Try again on the next one. Get faster and faster as the day progresses, but stay comfortable.
You’ll be classified as E Mod in novice class. This will have a “pax” to it. Like a handicap in golf. Don’t worry about all this and just go have fun.
Bring some tools (air gage, hand tools), sunscreen, food and drinks with you. It’ll be a long day.
Oh and have fun.