Tough question. I have a decent following on deviantart so I make sure to link to my Etsy from there and on my website. Usually I go to a few anime cons (can't get more direct than that lol) though don't know that it effects my Etsy shop so much. I've also tried pinning some of my items on pinterest.
I'm sure even favorites from other sellers help, since people can see their favorites :) Besides some sellers are are buyers too.
If you are involved with any other anime/geeky type forums or communities, just plop in a link to your shop in your sig or wherever you have a profile :)