One method you can use to evaluate the credibility of a given source is the SIFT method. This method consists of four moves that help you look at the source in the larger information context around your topic. It is designed to be completed quickly so you can determine which sources aren't appropriate and which ones are worth more in-depth consideration.
It is also important to consider what kind of source you have found. Different sources have different strengths, and will have more or less credibility in different contexts. The infographic below can introduce you to considerations for different types of sources you might encounter.