Some thoughts that work for newbies in many situations, not just folk clubs:

Keep a low profile and observe for a while, you will pick up quite a few of the conventions and ideas. You may also get a picture of the power structure, and the personalities involved. All this info is useful if you decide to get more deeply involved, and it helps you decide whether or not you wish to do so.

It is generally better to be considered enigmatic and interesting, than a brash blow-in that thinks (s)he knows it all. Make it clear you are open to guidance (checking with others before nabbing the best seat in the room is a good plan) You are bound to tread on somebodies corns at some stage so try to tread lightly, and be ready to jump back.

Finally, if you think you have a great new idea for the club, don't be too messianic about it; better to talk it over privately with one or two folks you feel confident with first. Your new idea may have been tried and roundly rejected before you appeared on the scene. If you don't yet have one or two with whom you feel confident it may be a little early to be suggesting major changes.