The best advice so far.
10 yards is nowhere near enough at any level over jr. high. We're doing 15 pretty much all the time except maybe on obvious kneel down plays. There's no good reason to be any closer than 12 yards at the snap otherwise.
Practice your signals in front of a mirror, and I'd get flash cards with the foul on one side and the signal on the other. Go through them until you know them forward and backwards. If you give good signals, everyone will assume you are a good R.
We don't wear white hats in subvarsity, including JV. Check to make sure you do.
I always get the coin flip call before a toss, have the other captain repeat, and say "If I drop it, we'll do it again." Practice that.
Otherwise, just have fun.