Step 1: Grab your favorite t-shirt. Make sure that it's a shirt that is at least a little too big, too small won't work!
Step 3: You're almost done already! Stretch out the arms, collar, and bottom (if you cut it) so it kinda curls up a bit and doesn't look freshly cut. Next, cut off the hems of both sleeves.
Step 4: Take the hems you cut off the sleeves and cut in half. You will have 4 short pieces of fabric. Take a piece and tie 2 or 3 knots near the collar on your front strap. Repeat this again on the front, and then on the back of both straps. Done!