Put your ballet shoes on, and tie the shoes with the elastic string so they feel comfortably tight.
Position the elastic straps over the tops of your feet. If you have two elastic straps that cross over your foot, cross them just above the arch of your foot. If you have one elastic strap that crosses over your foot, position the straps just under the midpoint of your arch. Make the straps firmly tight.
Draw a small mark on each elastic strap at the point where the strap must meet the side of the ballet shoes.
Remove the ballet shoes and pin the elastic straps in place where you will sew them.
Put the ballet shoes on again and make sure the straps are in the correct position and the shoes are comfortable. Try a few dance steps to make sure the fit is correct.
Remove the shoes again and turn them inside out along the openings of the shoes.
Thread the needle with approximately 15 inches of double thread and tie a knot in the end of the thread.
Stitch the elastic straps to the inside of the ballet shoes at the place you pinned them. Make small, even whipstitches along the entire outer edge of the elastic straps. Try to make your stitches as small as possible and only stitch through the inner lining of the shoes so your stitches will not be visible on the outsides of the shoes. Stitch down one side edge, across the bottom edge and up the other side edge. Tie a knot and clip the thread.
Repeat step eight to stitch the other ends of the elastic straps in place.