Mashable have written a nice article on the “Top 10 Ways to tweak Your WordPress Theme”.

The nice part is that even if you don’t understand they take you through the why you might want too and then show you how. Here are the 10 points

1. Edit Your Theme’s CSS
2. Display Post Excerpts or Full Content
3. Create a Custom Page Template
4. Crafting The Loop: Excluding/Including a Category
5. Crafting Your Page Navigation the Easy Way
6. Enabling Menu Management in WordPress 3.0
7. Create a Simple Conditional Statement
8. Add Post Thumbnails
9. Add Something (Anything) to the End of Every Blog Post
10. Add Google Analytics Tracking Code

To see the rest of the content you’ll need to head on over here.