Tip #1: Think before you search!
Tip #2: Use Google syntaxes
The video below provides a brief overview of evaluating sources for credibility. In particular, pay attention to the author or sponsor's education and expertise on the topic (authority), their point of view, and how current the information is.
If you're not sure of these things, check to see if the site has an About Us link that will tell you more. Also look for clues such as the site's language and tone, domain type (.edu, .gov, .org, etc.), and the presence and number of advertisements.