i rarely go out to see performers in the Atlanta area where I live. Many are novice songwriters who aren't quite accomplished enough to hold attention. Others have favorite performers they attempt to cover.
Here's the problem. To reach an audience that will support you, there has to be a standard set for high quality entertainment. Most of the pros won't do it for free.
Bluegrass has it's own venues and is covered as you know.
i think that you need to have performers in a variety of musical styles that have something unique about them. The audience needs to have as much fun as the performers.
This is the way it used to be in the coffee-house venues that I remember.
Try something that special in this area. Maybe a great local jazz singer.
Maybe a traditional folk singer who doesn't normally have a venue such as a five-string banjo player that sings Old Time songs. Maybe a virtuoso musician on guitar, piano, fiddle or any other instrument who needs to play out. Maybe a local blues singer.
A poet who has merit and no place to recite. A classical leider singer or opera or show music singer who has audience appeal. A small jazz combo. Maybe a recorder or early music consort. An East Indian sitar, tabla, singer etc. A good local Hispanic group or any representative of Atlanta's diversified ethnic community. Some great Celtic folks around here. Mix it up but keep it high standard. Look for those who don't normally have a venue in which to perform.
Also, be on the lookout for interesting non -pop type bands who may not be able to afford to be paid much because they are too large. Old-Time string bands, Celtic groups, jazz groups, singing groups (such as accapella stylists), early music consorts, brass quintets, woodwind groups, even good classical string quartets or quintets. Check the music departments of the various local schools such as GSU, DeKalb College, Kennesaw etc.
Important! Have a good sound system and a good sound system operator who really knows how to work it and make the performers feel good.
Don't get an M.C. who is lame or attempts to be funny. If you can find a talented one like Andy Offut Irwin, then you are really lucky. Above all, think of being entertaining to an audience first.
It can be done IF you keep the standards high. Then they will come.