You now know how to narrow down your search results, but you still need to evaluate your results for credibility. Consider the following:
Currency: Is the content current?
Relevancy: Does the content relate to your topic?
Authority: Is the author qualified to write on this topic?
Accuracy: Does the information come from a reliable source? Does it seem free of bias?
Purpose: What is the purpose of the content? Is it meant to be informative or to persuade an audience?