So, this is what you need:
10 - 15cm of faux leather
What you do:
Cut some leather/vinyl the length of your wrist, with about 1-2 cm extra.
Make a hole in each end, and thread the rings through.
Attach the clip on one side, and you're done!
I'm thinking I might add some studs or pearls on it, for a little oomph! :)