The First Commandment of Blogging

Thy Blog Shall Look Good, Yet Simple.

Some things look good, some don't. This is not a question of personal style. Bright green letters on a bright red background: not good. Animated gifs: not good. Wacky layout: not good. Comic Sans MS font: not good.
Adhere to the KISS principle: Keep It Simple, Stupid. But beware a boring-looking blog. Your reader should be relaxed, not comatose. Include images. Avoid black-on-white only.
Make your site usable. Make the archives easy to browse. Include a search box. Give your hyperlinks an obvious color or style. Make the main content stand out.