We have around 15 - 20 members, as any given month around 30-40% can't attend because of sick children, no babysitter, work or travel commitments, visitors etc. So typically around 8-10 people attend each meeting, which is perfect.
We meet every month, and we decide the books six months in advance, by a nominating and voting process (one nomination per person).
When the 6 books are chosen we alternate long and short, so you don't have two consecutive doorsteps. We only have fiction/novels. You are still welcome even if you've only read part of, or none of, the book.
There is no food involved, to keep expense and effort down for the host (which rotates every month), as we all have young children. The host just provides wine, water, maybe tea/coffee and nuts/crisps. However once a year, at Christmas, we do have a food night where everyone brings a dish, and we exchange books (second hand, always from our own bookshelves) as a Secret Santa present.
We meet for about 2.5 hours, and probably talk about the book for half of that time, the other half being general or related chat, or talk planning future book club events and ideas.
I love it, it's been a real life line for me!