This is my first instructable, so please excuse any mistakes.
Step 1: What Youll Need
Youll also need black sharpies. New sharpies work best. The older the sharpie, the harder youll have to press and pressing hard is difficult on a shirt.
DO NOT use red (or pinkish) sharpies. They will bleed on everything is the washer, including themselves.
Youll also need a piece of cardboard roughly the size of the shirt. They do make cardboard for this at craft stores, but for drawing on them in sharpies, a regular piece of cardboard works fine. I wouldnt suggest a pizza box, or anything else greasy.
Step 2: Getting Ready
Put the shirt over the piece of cardboard, as if you were dressing it.
Put the paper copy of the design you want in between the shirt and the cardboard. Line it up exactly where you want it under the shirt and tape it down.
Re-trace what is now on the shirt in a pen, or thin sharpie.
Fill in the areas
Any light lines will be hard to see and will require some free-handing.
Wash the shirt before you wear it, or else youll smell like the inside of a sharpie factory