Just go to the user CP, you'll find it on the top left hand of the page. Then choose "Customize Profile". Once you get to that page, it explains things pretty well. I found that I didn't really need to do that many adjustments to get a great looking page, I merely added, "wallpaper." I used about 5 different kinds where it says "background image" come over to my page, and have a look. While your there please make a friendship request, I love getting that message. You can also make a friendship request on other people's pages. It's so nice to have the message sent to you. Here's my favorite wallpaper link.
Backgrounds Graphics - Background Graphics for Piczo, MySpace