Quoted from nwpinball:
Suggestion, focus on the freeplay area. Get as many games as possible and do not let people pull games early or turn them off if they've sold. Let everyone that brings a game or two get in free to the full event, give people that bring 10+ games more perks. Work with local arcades to get large numbers of games in. If you have hundreds and hundreds of games on freeplay the entire show, you will see your ticket sales grow and grow and that will bring in more vendors and keep them happy. We've taken this approach with the Northwest show, every game in the venue is on freeplay, they must stay all 3 days, we have techs that keep the games running and the result is we draw about 4,000 people during the weekend and vendors often make more money at our show than any other show they do. It's the games that drive everything, after you have lots of games on freeplay coming, then start expand your efforts to other parts of the event.
And at least wipe them down and verify flippers working.