It's actually pretty simple. I will make another tutorial for some that a little more complicated later.
What you need are some needle nose pliers, an ear wire, and what you want to attach to the ear wire.
(I use 2, it's easier for me to hold parts with the pliers rather than my fingers)
(Simple ear wires. Try to match the ear wire to the piece, it makes it look nicer!)
Now onto the steps.
1. Take the ear wire and bend the small loop at the bottom so that the decoration can slide onto it.
2. Once you have the loop open, slide the decoration onto it.
3.Take the pliers and bend the loop back into place so that the decoration does not fall off.