I always bring more than one gun. You are not out of business if one has a malfunction that can't be corrected in the field. I also usually have a spotting scope, saves a lot of walking to look at targets. One club I shoot at insists on chamber flags to prove a gun is safe during cease fire, so that is always in my box too.
NRA sponsors a number of courses for pistol, rifle, shotgun, range safety officer etc. Check with the local ranges and clubs for courses they offer.