Cheers Dingle
Seriously, don't go out there hell for leather. Just take it easy, warm the car and the tyres up, and learn where the circuit goes.
Gradually increase your speed, so you don't arrive at the limits of the car or yourself too quickly.
Be aware of other people on the track - there is nothing BETTER than a track day novice who uses their mirrors and safely moves out of the way to let faster cars through.
At the same time, don't be TOO eager to move out of the way. It'll be obvious where the best places are to gently pull to the right.
Overtaking should only be on the left and on the straights.
Check all your levels including oil, water, pas fluid, brake fuid, tyre pressures etc etc and keep an eye on them throughout the day. (If you like your brakes, don't use your handbrake when you come back in after several laps of spirited driving!)
Slow in, fast out is the best advice you will take with you, so adhere to it - it does work.
Most importantly, enjoy yourself - it's supposed to be fun too!
Have fun mate