What is the best way to make a simple loop at the top of a headpin that will keep multiple beads on the headpin from twirling around (so that they stay stable and facing forward)?
The best way to secure a bead, or beads, in place on a headpin is to make the simple loop very close to and slightly inside the hole of the last bead. The pressure the small loop exerts on the hole of the bead will hold it in place.
Making a wrapped loop can also create this effect by making sure the wrap fits snugly against the last bead. When using this technique, be careful not to wrap too tightly so you don't chip your bead.