I'm not very good with Photoshop when it comes to creating backgrounds. I've tried a couple of times creating an image that tiles and it never looks good.

Can someone please tell me how they go about either creating or finding images that are used as backgrounds. Whether they are diagonal lines or just images that become one (ie. something that looks like an orage peel or something).

I don't have much experience making tiles in Photoshop, but you can take a look at...
http://www.stripegenerator.com/index.php?page=index
It's an online stripe generator that's pretty fun to play with.

You can create diagonal backgrounds using this tool

http://www.stripegenerator.com/

Lots of options download it as a .png file

Jim