Though its purpose is to target web design guidelines for government websites, this publication has long been a resource for everyone.
Download free: Research-Based Web Design & Usability Guidelines to view and print Guidelines Book by section
or buy the print version at the US Gov Bookstore for $25 US
This resource now contains 209 guidelines for effective Web design and usability and covers a wide range of Web site design issues, including home page design, page and site navigation, graphics and images, Web content organization, and effective Web content writing. Each guideline includes a “Strength of Evidence” rating that indicates how much research there is to support that guideline. It also includes a “Relative Importance” rating that shows how important that guideline is to the overall success of a Web site.