Jakob Nielsen's observation is echoed by other web experts. People generally visit web sites for information, and if they don't find it, they click away to another site without hesitation. There are millions of web sites with massive amounts of information, all indexed by Google. This means your web site's content must be carefully planned.
Here are several products prepared by Jim Alexander that demonstrate the type of up-front planning and analysis that a good site requires. They don't teach these skills in HTML 101!
A Web Site Analysis. Example of the type of broad organizational and technical analysis that a web site might be in need of. To Communicate Success and Excellence (PDF) is a white paper analyzing the characteristics, needs and challenges of an early version of the Rider University web site that was being rebuilt. Presented to the University Marketing Council. Illustrates a strategic managerial/communications approach to web planning.
Style Guide provides a thumbnail example of standards (PDF) that were prepared for the guidance of the dozens of (typically not highly trained) web page designers. While such standards have subsequently changed as people's computer equipment and viewing habits change, this is representative of design factors that a successful web site should reflect.
A Web Design Toolkit. A PowerPoint presentation prepared for a diverse group of university faculty and staff members. Designed to teach some basic considerations about how they should create good web pages and avoid common mistakes.Staying Current. Design and technical considerations are in constant flux, with new standards being introduced at breath-taking pace. These can be monitored, but the underlying objectives of a particular web site and characteristics of web users are critical as well.