I was an instructor (trackdays, rider skills and race school) at Cadwell for a number of years and the first thing to say is that you will LOVE IT! It’s a fabulous track with lots of different types of corners all in a beautiful setting.
In addition to the helpful on comments from folk on here already here's a a few tips I hope you will find useful:
Bike – we used to “scrutineer” before allowing bikes on the track, but it’s not full on race scrutineering. All we were looking for was anything which was likely to be a hazard to either the rider or other people. So anything which was loose and likely to fall off was a good way to get sent back to the paddock! You wouldn’t believe the number of folk who turned up with chains hanging on the floor, exhausts which had fixing bolts missing and fairings that were flapping in the breeze

As long as your bike is in good condition with everything in place you will be fine.
Mirrors – don’t bother taping anything, but I would recommend either folding your mirrors back or turning them downwards. You really don’t want to be distracted by anyone behind you (like an instructor sitting 3 inches off your rear wheel grinning like an idiot!) and you want to be totally focused on what’s in front of you.
If possible it is a good idea to trailer the bike to and from the circuit as you will be knackered by the time you finish. If you can’t make sure you take a break before heading home and take on fluids and food. Also give yourself time to adjust back to normal road speeds
You and your gear: An obvious one but sometimes forgotten - don't get wasted the night before!
With regards to clothing - in my day it used to be one piece or zip together two pieces leathers only but times have changed and I’m sure good quality CE approved textiles are allowed now – but do check the small print to make sure. I did work for Buell on one of their track days and a few folk got sent home for turning up in jeans (and I don’t mean motorcycle specific ones!). For one company I was asked to check every single helmet for a gold motorcycle sport sticker before they were allowed out, so it is worth just checking the T&Cs for what you have signed up to, but usually common sense prevails.
On the day – take your time and build up slowly. Don’t get sucked in by others and just ride for yourself and enjoy every minute. The most dangerous session always seemed to be the one just after lunch when folk have just eaten and their concentration has dropped so make sure you ease yourself back in after any break.
Use the first lap as a sighting one and warm your tyres up. Believe it or not I had more than one customer crash in front of me in the pit lane caused by them going mental on cold tyres as soon as they set off.
If you can get an instructor to show you the lines and coach you a bit then take advantage of this. They usually know what they are doing and are paid to help you to get the most out of your experience.
And finally – the one thing I seemed to say to customers more than anything else on every track day I did:
Relax and turn your f*cking head to look where you want to go!!!!!
The number of folk who tense right up and look 3 foot further than their front wheel is amazing and will completely cock up your cornering. Look up, turn your head and look for the exit!
That’s the key bits from me – enjoy your day, you will have a fabulous experience and it can be very addictive

