Prepare yourself physically -- the first day of camp will include a beautiful hike. Start preparing now by going for walks or hikes with your friends and family. You can build up endurance by starting with short hikes and working up to long ones, start with easy, level hikes and work up to more steep or strenuous ones. Also, camp is pretty busy with lots of walking between different activities. You're preparation for your hike will help you all week at camp.
Prepare yourself mentally -- start thinking of ideas that follow the theme for your year-group skit, see if you can remember the names of everyone in your group from last year.
Go over your packing list early to make sure you'll be prepared with all you need ahead of time (mom's appreciate advance notice 😊). Make sure your clothes fit the dress standards.