I know I posted not long ago about how to dye fabric, but I just had to share this cool shirt that I just made. I must admit that I just recently tried tie-dying for the first time. I don't know why I didn't before, because it's so easy. But rather than tie-dye with multiple colors and getting that awful hippie look, I dyed mine one color.
I just bought some inexpensive white tank tops, and I already had a few boxes of fabric dye at home. All you do is pinch the middle of the shirt and tie string or yarn around it (I learned the hard way that rubber bands do not work) and then keep going up the shirt, tying more lengths of yarn as you go. I did one big circle on the front, but I made lots of small ones on the back.
After you have tied up your shirt, dye it following the instructions here. Then rinse, run it through the washer, and hang to dry. It's that simple! And I definitely will be making more of these soon.