Find or create a backdrop that complements the color of the T-shirt you are photographing.
Ask for a friend's permission to use his image on the Threadless website. Ask your friend to model in front of the backdrop wearing a blank crew-neck T-shirt.
Take a photo of your friend with your digital camera. The front of the T-shirt should be clear, unobstructed and the main focus of the shot.
Take a photo of the back of the T-shirt if your design goes on the back of the T-shirt.
Edit the photo using photo-editing software, if necessary, to crop it, balance lighting and add design elements to the background.
Launch your graphic design software. Create a document that measures at least 640 pixels by 800 pixels.
Draw the shape of a T-shirt using a thin black outline or an outline that is slightly darker than the T-shirt's main color. If you are having trouble drawing the shape, trace around an image of a T-shirt.
Fill the T-shirt with a color that complements your artwork.
Duplicate the image and raise the T-shirt's collar if your design is also going on the back of the T-shirt.