Everyone above has given great advice. The only thing I would add is to not rush out and buy everything at once. Buy just what you need to get started, then take the camper out on a short, local trip to try things out. See what you forgot and can't live without - then pick up those items.
As you camp more, you realize more items you need. You also see how other people set things up and will get ideas from there.
This way, you don't have to spend a fortune to get started, and you won't end up with a lot of stuff you won't use that often.
