FREE is good! No dues, and no meetings other than at the water. If someone wants to throw a party and invite other divers great. Meeting at a bar okay, but not a requirement by any means, but instead just a social gathering put out there for all to attend.
Make sure the club offers new divers and members a warm welcome and that they can buddy with a more experienced person if need be. Usually we set a designated person who is the greeter, and makes sure everyone is taken care of.
For protection there should be a signed waiver on file, which also has emergency contact info. My theory is this should be available to a multitude of people in case of an emergency. Maybe even stored online in a PDF format, not accessible to all, but to trusted members.
There needs to be some kind of website, or place to post. Meetup is becoming very common these days for organizing events.
Events need to be planned far in advance. As someone mentioned there should be boat trips available to all, and then cost effective shore diving if possible.
The single most important thing, actually to get in the water and GO DIVING!