take a desire length you want and stitch a layer of stiffening and a lining over it.
turn over and stitch a border or leave it as it is and at a required distance stitch a small piece of velcro.
then stitch the other part of velcro at the top of the zip.
After finishing these two sides, attach them together and invert it i.e. inside out. And again stitch a straight line all around the clutch and your clutch is ready to use. heres the finished work pics...