Start with an oversized T shirt and lay it out on a flat surface.
From the bottom hem measure the desire shortest length of your skirt. I went 12 inches from the bottom. Mark with chalk.
At this point you can simply cut across and make the skirt one-length. I chose to cut on a bias. For this, mark just below the armpit of the opposite sleeve and cut diagonally.
Finally, make a little snip in the hem and thread either a string or a pretty ribbon to make a drawstring.
That's it! Easy Peasy!