Step 1: Materials needed
Don't stop there though - go crazy decorating! Add jewels, appliques, iron on transfers - or as this instructable shows - screen printed floral border.
For screen prints you can use any type of t-shirt material. For iron on transfers, I have found that 50/50 t-shirt material is the best. Cotton tends to have too much "moisture" within it that the ink does not adhere well.
When in doubt, read the instructions on whatever image process you are using.