Bike prep: Tape up all the lights (headlights, tailight, and turn signals). I use painters tape. Make sure your chain is adjusted properly. Tires have decent amount of thread left.
Gear: 1pc or 2pc leather. Racing boots that cover your ankle. Full guantlet gloves that cover your wrist. Full face helmet, DOT/Snell/ECE approved.
You: Drink plenty of water before, during and after the trackday. Also, I would suggest drinking plenty of water the day before as well. You're body will need it especially since the recent heat wave. Leave your ego at home. Be ready to learn and have plenty of fun.
Bring your own food for lunch. Monticello doesn't any facility for food so bring some sandwiches or some snacks. Avoid trying to stuff yourself too much LOL. Also, If you have a Gas can laying around it might help as well towards the end of the day or just make sure the bike is topped off before you hit the track. There are no pumps at Monticello either.
TPM is decent org. They have instructors that can help you out. Take advantage of them.
Monticello is a fun track but you have to be very careful on the first couple of sessions out.... Just take it easy and you'll be okay.
Have fun meng, you'll be bit by the track bug after your first day. You'll be itching for more track time.
I wish I was at the track.