Word of mouth mainly. I have lots of steady clients and repeat business. And they in turn pass my name along. As for art, I just post to every art site I come across.
I'm surprised that I've never heard of Barry Winsor-Smith. Just did a google search on him and he's worked on alot of cool comics. You're right, he does great detail! How about Whilce Portacio? One of my fave comic artists.
Whelan rocks, man!
He has that nice balance between traditional and digital works. My favorite piece by him is his "Golden Key" self portrait. Yeah, Whelan is cool.