Fold your tea towel in half with right sides facing each other.
You'll make boxed corners. Instead of measuring and sewing off triangles. Simply take the folded bottom edge and push it up between the front and back of the fabric, creating a pleat.
Pin along each edge, making sure the folds line up at the bottom of your bag.
Zig zag stitch in a straight line along both sides.
Pin and stitch your handles into place. If you're using webbing, I recommend sewing it on with a boxed "X" to provide more support.
Flip it all right side out to use.
Video
Notes
My braiding was a little thick and finicky, so I just zig zagged back and forth a few times.