Asking these questions will help you to determine whether the resources you find are credible and reliable.
Who created the page? What is their background with relation to this subject?
Why was this site created? What is the purpose of the site?
For example, is it sponsored by a company that has a financial interest in the topic?
What do others have to say about the site or company behind the site?
When was the page created and/or last updated? How current is the information?
Does the author cite their sources? If not, how does the author support their argument?
How does this site compare to resources your professor recommends or assigns?