The sides and back are basicaly the same, sand with sandpaper like you would with wood. Then burnish, I like using sadlesoap, some people use gum trag, but after it looks like you want it to you should be able to paint or dye it however you want. The gum t acts like a resist though so it might be hard to dye after. Bob park has a great tutorial about how to finnish edges that is the best I've ever seen. And like they say, practice makes perfict.