Nothing new on race day!

^^I'm assuming that bit of triathlon logic would apply here as well. Don't eat anything you've never eaten, don't wear anything you haven't worn riding(might be hard if a group hands you a whole kit that day, maybe take that with a grain of salt), don't put brand new tires on your bike the night before, don't eat a new kind of gel or bar or breakfast, don't drink an new kind of drink, all that.

Good luck! Have fun!