Couple of things to think about...You need a venue that won't mind a little water spillage - usually hard floors not carpet. Also make sure there is plenty of power - alot of people want to bring small tanks 10-40 gallon to set up with pc lights. Also access to fuse panel in case a fuse blows ( happened at our local club swap.Not fun if you don't know where the fuses are !!) raffles, raffles, raffles - these help bring people in more than just about anything. Also once you get a deff date put up a thread on most of the club forums that are even kinda close. Get people talking about it. Here, RC, living reefs etc - the more the merrier!! it is a lot of work but it is soooo worth it when it all pulls together
Sorry if this sorta bounced around - just brainstorming from our swap
Patrick