Start with cutting a rectangle out of your fabric. I then hand-sewed all the sequins, this part takes the most time. It doesn't have to look neat, the messier the better!

This is what it looks like when all the sequins are sewn on.

Next, cut out a piece of felt and glue it to the back.
I also hand-sewed all the way around to secure, but that is not really necessary.

Finally, place your bobbi pin (or another type of hair clip, like I did) on the back, cut another smaller piece of felt and glue it all together (as you can see in the picture).
Let dry and you're done :)