Here's how I made them below. It was quite simple.
Step 1 (Optional): Embroider name on fabric. I have an embroidery machine so it was easy. Although I did have to go over the letters twice. Really high loft fabric does not embroider well. Although it did seem to work better when I loosened the tension to 2. UPDATE: I read that if you use clear vinyl (like tablecloth vinyl) on top of your fabric it will look much better. That, or water soluble stabilizer.
Step 2: Lay your skate on top of your fabric and cut fabric so that it is twice the size of your skate's blade. If you embroidered a name remember to center it.
Step 3: Turn fabric to wrong side and cut fabric so that it is 8" wide and fold in half lengthwise.
Step 4: Sew one end along the shortest edge.
Step 5: Sew a Curve along the opposite short edge and trim excess.
Step 6: On wrong side of fabric, fold over top edge by 1/2" and sew along edge leaving about 1" open. This will be the casing for your elastic.
Step 7: Cut your elastic. The length will depend on your elastic's give. For weak elastic, cut the length 1 + 1/4 the length of your skate's blade. For strong elastic cut 1 + 1/2 the length of your skate's blade.
Step 8: Thread the elastic through the casing using a safety pin. Be sure to secure the end of the elastic with another pin so that it doesn't slip through the casing, see photo below.