High rankings on all major search engines are influenced by the number of web pages that link to a web page and by the quality of the web pages that link to a page.
Links from popular and trusted web pages have a bigger impact on the search engine rankings of a web page than links from less popular and trusted pages.
A new patent application with the name "Ranking Domains Using Domain Maturity" indicates that there is another factor that helps search engines to determine the quality of a web page.