Cut a strip of elastic and slide a small bead in to the middle.
Slip on two larger beads at either side of the small bead.
Slip a small bead on one tail and then slip the other tail through too.
Continue this along until you have enough beads to fit around your finger, but don't add a small bead on to the last set.
Slip the loose tails through the first small bead you placed on the elastic, tie in a knot and then cut of the loose tails.