Mary has covered most of it I think. A pit band makes a huge difference and lets the entertainment start promptly even if there is a shortage of floor singers.

Good chorus singing from the audience does wonders for the atmosphere but you need a core of strong singers for this to work.

It is vital to remember that people are paying money for what you are offering. If they feel cheated not only will they not come back but they will slag off folk clubs in general to all their friends.

Meeting and greeting is vital. Punters remember the door crew and expect the door crew to remember them.

Build a good team to help run the club. There are a lot of different skills needed, it is unusual for one individual to have them all.