My first DE I minmized caffeine intake. I had more than enough adrenaline to compensate.

Minimize your shifting so you can work on your line and braking.

If you can find somewhere (empty parking lot or little used road) ahead of time, build up some speed and practice braking hard. The Cayman has great brakes, learn to trust them.

I would think twice before I let anyone else take my car on the track. Who is responsible if something breaks or is damaged? Definetely ride with an instructor every chance you get. At some point sneak a few glances at their hands, watch how smooth their inputs are.

Be prepare for some sensory overload the first few times out if you are not used to driving at speed. There will be corner workers out there that you probably will not be aware of at first because your brain is processing all it can handle watching the line, driving, and dealing with instructions.

If you are saving money to buy a house or put your kids through school, put that money in a trust where you cannot get your hands on it. After the first DE you will be trying to figure out how often you can get back and what mods (tires, brakes, wheels, suspension,etc.) you can get. The term addiction is used a lot. Just kidding.

Have fun!! It is a blast!