This is by far the fastest and easiest tutorial I've ever posted. From start to finish it takes less than 5 minutes!
-largish jump ring
Step 1: Pick an area to remove a jump ring by opening it up with 2 pairs of jewelery pliers.
When you're done, the two ends will look something like this.
Set the jump ring you removed aside for now. You'll need it in step 5.
Step 2: On one of the open ends, attach a new, slightly larger jump ring and close it.
It's unlikely that the length of the chain as is will be a perfect fit for your wrist, so now is the time to figure out the correct size.
Step 3: Wrap the bracelet comfortably around you wrist over and over until it can't go completely around again.
Step 4: Use snips to cut the extra chain at the point it meets up with the large jump ring.
Step 5: On the ends you just cut, attach the jump ring you removed in step 1. Now slip a clasp onto that same jump ring and close it.
When you've finished the two ends will look like this:
Step 6: Put the bracelet on, so if there are any issues with the fit you can adjust them. (It's easier to just go ahead and do it now while you've got the tools out!)
Now this I will wear.