Cut a piece of cardboard to the length you want your tassel to be. I often use a CD case for this.
Wind yarn around the cardboard four or five times.
Cut the yarn at one end so that you have equal lengths together.
Pull the middle point of the lengths of yarn through the garment close to the edge using a crochet hook or something similar.
Secure the tassel by pulling the loose ends through the loop.
Trim if necessary.
