First decide how big you want the bag to be.
*For the height, add 1 1/2" to the top and 5/8" to the bottom.
*For the width, double the size and add 1" to each end. If you have a serger or don't care about neat edges you could just add a standard 5/8"
Next, fold over the ends 1/2" and press, then fold over again and press again.
Next, fold and press top down 1/2" the. fold and press again to create a pocket for string.
Stitch along edge of the top fold to create pocket