my old blog was deleted when my account got deactivated so I'm sharing this again with all of you. this technique can be applied both traditionally and digitally:)
STEP 1: Draw something in the middle of your paper/screen. DO NOT go to any edges (as tempting as it may be don't!) As soon as your satisfied with what you have move on to step two. (I doodled a dog wearing a sweatband.)
STEP 2: Take your drawing and cut it EXACTLY in half vertically. Yes, cut it! (if you are doing this on a computer it's not a terrifying) Once you've done that flip each side and then place them back together so your drawing is now on the outside edges of your paper.
STEP 3: Take your drawing and cut it EXACTLY in half horizontally, go ahead and flip each side so you now have your drawing in each of the four corners of paper.
STEP 4 Here's the fun part! fill in the center space of your drawing. Be careful not to go to the edges of your design, this is important here too! Once your satisfied, sit back and smile:) If you're working on traditionally now would be the time to scan it and open it in your favorite program.
STEP 5 I use an old photoshop program so I hope this is an option for the rest of you. Select your whole image and go to edit "Define pattern from selection" Name it what ever you like.
STEP 6 Open a new file that's larger than your current file (40x40 inches is the size needed for a belt print on threadless, just FYI)
Use your paintbucket tool and select pattern, find your pattern name select it and fill in your black page with your awesome pattern:)
STEP 7 :) "Tada" You're done!