What you'll need:
Jeans, thread (can be blue but any color is OK), seam ripper, pins, scissors
Step 1: Using a seam ripper, open the inner leg seams from the lower edge to the crotch seam on the front side of jeans, and on the back side, open the seams farther, about even with top of pockets.
Step 2: You'll end up with strange flaps if the jeans are laid flat from step one. Lay them flat but overlapping and pin them together.
Step 3: Put on the garment. Adjust pins at the center seam according to how flared or how long you want the skirt. Sew it into place (be careful to only sew one side at a time—don't accidentally go through all of it).
Step 4: Cut off legs where desired. Sew the removed leg portion into the open part of the skirt. You can sew it all together, or leave flaps open for walking if tight.
Step 5: Trim the lower edge of skirt evenly, and machine stitch it two inches from the bottom to prevent fraying during future washings.
Extras: Iron the skirt so it has a finished look; add lace, fabrics, ribbon, sequins, etc. to give it flare.
—The Home Sewing Association
