High quality artwork isn't as important to me as consitent artwork. Obviously I'd want it not to be bad, but simple and abstract is perfectly fine. I'd go for comic book line drawings, maybe like Cerebus over stuff created in blender, or attempts at more detail that fail.
If it's free, I wouldn't really care about the publisher. Even paid it isn't that big of a deal. More options than just Lulu would be really nice though.
Good reviews certainly help, especially ones that highlight something interesting and unique about the game. The latter bit is probably the most important. There's a ton of systems out there, so the game would need something that isn't offered elsewhere.
Showing up at the FLGS is nice, but certainly not necessary.
Interesting premise will vary from person to person, but certainly I'd only play something that interests me.
I have a strong preference for trade paperback sized books over full sized ones, and it seems to be a direction that a lot of game designers are taking.