I'm a photographer and for the past month I've slowly been adding my work to Society6 in hopes of making some additional income, but unfortunately I've yet to see any sales. Don't think many people coming to sites like this are looking for art prints to be honest. I'm still hopeful that if I'm consistent about uploading work I'll eventually make a few sales here and there. Part of it is just getting popular on the site in the first place.
RE: How to make decent money selling designs on POD websites.