set up early and stay late.... and bring lots of cash! I never made money at shows because I always spent more than I made ...lol ... around here (RI) dealers gave dealers crazy deals at the end of the show during pack up time!
As one other said, set up early, stay late. Be open to making trades. Bring plenty of spare change to get some great deals at the end of the show. I've made money at shows, good money in the past. Especially show up with what ever players are hot in your area, also the hot players to collect right now. Most importantly, just have fun with it.