Color immediately came to mind. A great article on SE themes and how they help you rank higher in the engines. I don't think I need to say much about the importance of your site design. Meta tags can increase your visibility in search engines, which in turn means more visitors to your website. J. Edwards reviews a few meta tags you probably know, and a few you may not have seen before.
Many web designers overlook the importance of color when designing a web site.
Testing is a critical part of Web development. For your site to function, and to generate good client references, Quality Assurance is essential. A new study done by a joint project between Stanford and Poynter reveals the truth behind how users browse through the Internet. Discover the science and strategies behind color on the Web, then create an effective color scheme for your site. Webmonkey's insider guide to getting and keeping the most traffic from search engines.