There are a lot of great websites out there, and a lot of duds. How can you tell the difference? This guide has some great tips for Evaluating Internet Resources.
Another tip for separating the good from the not-so-good is doing a search that limits the results to just a particular type of website, such as education websites. In Google it is done like this:
"august wilson" fences site:edu
Another method is to use a search engine like Google Scholar, although this mostly finds scholarly journal articles and books, not typical websites.