Around your neck, doubled up on your limbs, or around the waist. Wear it anyway you like, but I have to say, I'm majorly OBSESSED with the clean yet strong look such simple pieces of hardware can provide.
Want to pack a punch? Buy two of the same piece (or pack of two) and wear one on each wrist, arm, or ankle. Own the room and wear a thick cuff around the neck as a choker.
Often seen in metal, I'm actually quite fond of the DIY version in acrylic from Love-Aesthetics. (The one I did myself is the last picture after the break!)