I live alone so sometimes have a difficult time putting a bracelet or watch on by myself so I tape one end on my wrist with cellophane tape so it stays put and then I can take the other end and hook it together. Works every time!
This page contains the following solutions.
Need help clasping your bracelet on your wrist? Use Scotch tape to hold down the "eye" end, now just open clasp for attaching.
Wearing a bracelet with a clasp takes time to put on. It can make you angry sometimes or even fall off when it is already on your wrist! I just cut a small piece of Scotch tape, put my bracelet on my wrist and tape it on. That way, I can hook the clasp on the ring of my bracelet without it falling off my wrist.
Bracelets and necklace clasps come in myriad of shapes and styles. This is a page about fastening a bracelet.