I also think an introduction of the characters at the beginning of the event would be a cool idea, and have a cool announcer do it like it's a basketball game or something and get the audience going. |D So the people who haven't watched that anime, haven't read that manga, or haven't played that video game can at least know their names...and if the cosplay is hard to identify (maybe due to likeness to another costume, due to school uniform costumes and such), then they can know who's who.
Also...got this from SakuraCon's website, after their own first Cosplay Chess:
"For next year, I would really like to see the spaces numbered and lettered "3A" "4A" etc.. Mainly because that would make it easier for the chess players to move people (and also so they don't have to come out on to the board to move people) and because, and I had this in the rules originally, I would like for the pieces to leave the board for a battle... so the audience has a clear view, and so no one gets hurt."