When we started our club, there were only the 3 of us co-founders.
Our club is very, very, very laid back. No dues. No officers. No agenda, other than to share beers and techniques, and help everyone learn to make better beer. We meet upstairs at the local brewpub as a closed private event away from the rest of the patrons (which allows us to bring our homebrew to share without voiding their license). We always order beers and food from the pub, too, and tip the staff very well, which keeps us in their good favor. We also often let a few of the servers sample some of the best homebrew, which they enjoy, too.
We grew, albeit very slowly, over the last 10 years, from the 3 of us to where we now routinely get about 18-25 folks to show up at the monthly meetings, out of a membership we think is somewhere between 40 and 50. We don't know the exact number, and frankly don't really care too much. We know that our email list has 60 names on it. Several are friends from other clubs so we can cross-post news when applicable. Others are folks that joined up but stopped coming, or moved far enough away that they don't come to meetings any more. All are still welcome, so we don't drop them from the list. The only emails that get dropped are those that bounce and even then we keep them on hold until their server reports the account closed.
Other clubs are much more organized and regimented, and that's fine too. Most are somewhere in the middle. Your best bet is to see what the membership wants and go with that. It may change over time, too.
HTH-