>>'This may be different with a band with the instruments on the picture, as people may look at the picture and think "Uhhhmmmm thats interesting, I think I will go and see them". If I put a poster of Vin Garbutt up it wouldn't do a lot in my area as most people wouldn't know who the hell is Vin Garbutt.'<<

As that is my quote, I will tell you how it would work with Vin at my place.
Vin's website and mail list do an aweful lot to getting people in to see him.
My website which gets regular viewing from many people, supports that as well.
The local newspapers with a write up about the performer and picture, will also work.
Local radio folk program and Folkwaves is also important as they read the diaries out.
People are handed a diary of upcoming events when they attend my club.
I make sure my events are on the main folk websites around here, such as FolkTalk and Fizgig plus others.
Links to my website on other peoples websites is also helpful.
The rest is very much word of mouth.

As I have 5 performers every other week, I work on the basis, that if they enjoy the club, they will tell others.

Oh almost forgot, I post on Mudcat - you never know, it can pick up the odd person. If you are thinking ODD - well taht as well LOL :-)

Anyway, theer you have it. If you run a club and invest a lot of your own time in it, get out there and let people know. Above all make sure it will be an entertaining evening, so taht people will hopefully come back again.