Download a Threadless shirt template form the "Threadless" website. This template helps you to arrange your design onto a T-shirt shape and prepare your design for submission.
Design your shirt in a vector program, such as Adobe Illustrator. You can draw your design in the program and then convert it to a vector drawing using the "Flatten Images" in the "Object" menu.
Go to "Participate" on the "Threadless" website. This link will allow you to upload your shirt design onto the web.
Enter your design for a Threadless critique before submitting your shirt to the voting public. By inviting criticism, you can gain perspective on your T-shirt design and make any changes to tweak your design into a winner
Monitor the "Threadless" website. You might want to tell your friends to give your shirt a high rating, but you'll also want to respond to comments that other Threadless users put on your T-shirt voting page.