This is going to be quite a long post, but, don't let that intimidate you. Once you go over it and understand it, it's not difficult at all. (Although it requires lots of drying time.)
I recently saw something on Pinterest that caught my eye. CD scratch art (link at the bottom). I actually didn't look at the tutorial, and had wanted to look at the picture to copy my design, but none of that happened. So I ended up making a few mistakes, but now I know.