1. Fold down the heel of your ballet shoe flat against the lining and use a pencil to mark where the folded upper meets the binding on both sides of the shoe.
2. Stitch one side of elastic onto the sock lining and binding but be careful not to stitch through the drawstring or the ballet shoe upper.
3. Put on the ballet shoe and pull the elastic over the instep, place a pencil mark where the elastic meets the binding and stitch the elastic to the other side.