Threadless

So after my recent senior portfolio exhibition, I've been getting a fair amount of bites on my shirt illustration piece. I am the early stages of considering pursuing this on my own time, freelance if you will. I know I am going to need to keep my options open. Especially when I am graduating without a job (that's a whole other headache though). Reading through sites like Threadless are the right places to start. So until I acclimate myself more, anyone have advice?