• Design: Testing on multiple browser capabilities, and screen sizes and resolutions. Valid HTML and CSS coding.
• Navigation: The ability to find information
• Usability: Including features that aid users and avoiding those that irritate them
• Content: Information in the language of your users.
• SEO: Optimizing a site for search engines is more than improving your rankings, it’s about engineering your site so users can find it using a search engine — clear content and keywords.
• Social Media: In May of 2011, US web users spent 53,457,259 minutes on Facebook. Nielson reports that people don’t like doing business on Facebook. But a personal website might be effective.
• Tracking and Analytics: 80% of all websites used Google Analytics in 2011, but the important thing is using the data from your analytics to  learn what your users are reading and looking for on your site, and how they get there. That doesn’t mean being user driven. It does mean looking at what is important to you and measuring it against what your users are viewing. You may need to present yourself more clearly.
• Footer: Don’t slack off at the footer. Repeat navigation links, include your copyright, and contact information, including your company name.

The infographic from Visual.ly: