Before you put down a single pixel in Photoshop, or choose a single typeface or color palette, you should plan out how people are actually going to *use* your site.
Designing a site is about graphics, sure, but it’s also about designing the information to ensure that it’s easy for user to find and interact with. You can have the most beautiful graphics in the world, but if your audience can’t figure out how to find the information they need, your site won’t be successful.
When a large web design studio does a project, they spend the first part of the project planning it out. This is a vital step that a lot of small shops and DIYers tend to skip. A theme may jump-start the visual design of your site, but you still need to think about what you’re putting into the theme, and how you want to organize it in order to achieve your site’s goals.