Early paperwork is good advice. Among volunteers make sure you have one designated as a photographer. Everyone likes to see their picture on the website later.
Try to aquire pilot gifts if it's a fun fly or open event.
If you are not a gold leader club and want to be one using an event to generate a donation to a local charity or non-profit will help you with that goal.

I'm thinking about doing a sun-up to sun-down event next year. Where the goal is to have at least one plane in the air the entire time from sun up to sun down. I'm thinking it will be harder than it sounds.