The dancer should try on the shoes while wearing tights and adjust the drawstring for a snug, conforming fit.
With the shoe off, fold the heel down so it is flat against the inside bottom of the slipper. Make a small mark on each side of the inside of the slipper just below the binding where the fold meets the edge.
Put the shoe on. Find the most comfortable spot on the instep for the elastic. It will fall somewhere between the center of the arch of the foot and the mark that was just made. Make a larger mark on the lining of the shoe to show the stitching position for the elastic. Pin one end of the elastic to this larger mark.
Stretch the elastic straight across the top of the foot to the outside edge of the foot. Make a mark on the lining on the outside of the foot to show where to stitch the elastic to the shoe. The elastic should be snug across the top of the foot so that the slipper and the elastic do not gap, but loose enough so the dancer can easily fit two fingers underneath the elastic. The elastic should not pinch the foot; if it does, it is too tight.
Once you’ve determined the elastic fits properly, mark the elastic to show the stitch line. Pin the stitch line on the elastic to the larger mark on the lining on the outside edge of the foot.
Use the heavy-duty needle and thread to stitch the elastic to each side of the shoe where pinned. Stitch just below the binding and be careful not to stitch the drawstring. Knot one end of the thread. From the inside of the slipper, pass the needle through the elastic and then through the shoe. The elastic can be secured either by a straight line stitched across it or by stitching an “X.” Repeat the line or “X” several times to ensure the stitching won’t break. Finish off by knotting the thread and trimming it. Remove the safety pin. Repeat on the other side. The dancer should try on the shoe before trimming any excess elastic.
Repeat all the steps above with the other shoe.