Just as every book and author is unique, there's an endless variety of blog styles and flavors. All the blogging services have page templates, allowing you to start with a basic design and add a few personal elements.
Don't get bogged down looking for the "perfect" design. You'll always be free to tweak your design later, or do a complete overhaul. The most important thing is to get started adding content and building your audience.
The main design requirement is readability. Plain vanilla blogs are fine, and are actually preferred by most readers--it's the words that count. Black text on a white background might seem uninspired, but it's much easier on the eyes than white text on a black background or some other color. A plain masthead, simply your blog title in capital letters, is fine to start. The important thing is to get started.