Well, first of all we should have regional representation. Start of with perhaps only 4 or 5 regions (Scotland, North, Midlands, West & Wales and South & East) and get at least 1 meetup going quarterly. You can increase frequency as number or desire dictate.
There should also be 1 national meetup per year where we all get together for some grub, a chat and some photos.
Everyone should be showing where they are from in their profile. With this in mind it might help to encourage people to get together to help those who are living nearby. I'm in Munich by the way so if anyone fancies a cuppa at my place, it's down to Dover, onto the Ferry and straight on at the motorway for a very long time.
Mechanically minded members could have a spanner icon in the signature to denote that they are an authority on technical stuff. The forum admins would have to determine this.
Newsletter are largely a waste of effort in my opinion. The only real benefit being that you get a piece of paper with a few Camaro friendly garages, parts suppliers etc.
No need to re-invent the wheel here, just copy the good things that other successful clubs do.