I think the best (free) thing you can do to drive sales is be yourself and window shop. Heart other people's stuff, share it on your fan page, be active in teams, looking at what's there and hearting, Remember that especially on Etsy, what comes around goes around. The more people who see what you have to share about others, the more people will share about you.
If someone adds some of my lampwork to their favorites, I find something in their shop I like and share it. I may only fave it, I may tweet it and I may share it on FB, but the end result is that we both benefit.