I love making these little felt barrette covers- they're cute, and the barrettes stay in place.
They're really easy- make a pattern by tracing a snap barrette onto a piece of cardstock, then cut a little bit outside the line. Cut out, and trace THAT pattern piece again to make the bottom pattern piece. Cut out the bottom piece, and cut in half.
Now cut around both pieces on a piece of felt, decorate the top, and sew around the edges! You can either just slide the barrette in and use as is, or find a good place to stitch the felt to the barrette. My barrettes had a little tiny hole in the top, so I used that. If you look closely at the picture, you'll see some extra stitches securing the top "lazy daisy" petal, and on the other barrette you'll see a green bead that looks a little closer to its neighbors.
You can search on etsy.com for lots of great examples of felt barrettes. People are really creative!