The two main criteria underlying what makes a great website are (1)-How search engines view it and (2)-How visitors judge it and react. The website owner, search engines and visitors all basically want the same thing, that being a website that is attractive, easy to locate and containing relevant information to their search.
There are many, many things a webmaster can do to make his website meet the criteria that results in organic free traffic (lots of visitors). Just a few of these include:
Avoiding too much duplicate content on website pages
Utilizing a proper sitemap
Avoiding the overuse of flash and animated banners
Obtaining quality links to relevant websites
Wise selection of Meta keywords included in content
Submitting articles to active, respectable article sites
Unique and compelling content
Validate and 508 the website for accessibility
Use RSS Feeds
Use plenty of PR
Be visible on high traffic social networking sites
The above are just a sampling of the more than 75 criteria Top Quality Ranking applies to every SEO program.