All you need is an old tshirt and scissors.
1) try on your tshirt. mark the height where you want your fringe to start by make a small snip, then take off the shirt.
2) cut off the bottom hem.
3) make your first vertical cuts on the two sides of the shirt, cutting up to the point you snipped earlier.
4) starting from left to right, make slits of equal height all along the shirt (cutting through both layers). you can make them as wide as your little heart desires. i made mine about .5 to 1.0 inch wide.
5) slightly pull apart each fringe piece at the top
6) cut off the sleeves of your shirt. try it on to see how you like it. if the shoulders are too wide, just keep trimming until you love it!