|You can use any elastic, but 1/4" is good....it doesn't have to be that clear elastic. Secure the top of the elastic to the fabric with a pin or a tacking stitch, and put the needle in the elastic when you put your foot down, then stretch the elastic to about double the length you want it to finish. Then zigzag thru the elastic as it is pulled taut. When you reach to end point of where you want your gathers, stop and back tack. The fabric will scrunch up once you let go of the elastic and it recovers its shorter length.