The most important step in making these is having the right tools to begin with.
It's essential that you have a strong adhesive; one that can bond metal to metal, for example.
Other tools that are a must have are a pair of needle nose pliers and a toothpick or two.
Get your rhinestones or gems out and test them. Make sure they will fit into the eye sockets (or other areas for whatever other charm you may be using).
Gather the stones or gems with the pliers one by one to glue them. I used one toothpick to apply the glue to the underside.
Place them in the eye socks one by one as well. The adhesive starts to dry quickly, so you need to position them fast. I used the other toothpick to move them around.
Apply some pressure to each gem as it is positioned. They will start to stick quickly, but they need plenty of time to dry.
The jump rings can be added after at least 10 minutes have passed. This is to ensure they gems don't fall off when you pick them up.