Learn.

I got it a week ago too, but I have alreay figured out the basics and did a little theme modifying (mainly adding icons to the desktop) and plan to make my own theme soon, I just have to figure out a couple more things first.

Believe me, it is easier than it looks. Once you get used to the modular system and the syntax, you start to see how it all fits togeather. The best way to start would be to just play around with the settings on a theme you already installed to see how it works.

Good luck :)