You'll need to be sure to register/ check-in when you get there. Some shows require you to leave an open check, others let you pay ahead of time. You'll also have to show your coggins test at check-in. Get a couple of class lists for yourself so you can remember what classes you're in :)
Also, arrive early. By an hour or more. That will give you enough time to get there, get settled in, get your horse settled in, check in, ride, etc. etc.
I hope you have a blast! The local shows are always so much fun (and so much more stress free!)
PS - don't forget things like 2 buckets (one for water and one for sponging off your horse), hay, manure fork, fans and extension cords, etc. etc. :)
Sorry for the scattered thoughts...really tired, should be sleeping