The following are some good guidelines for recognizing what type of source (scholarly, popular, political, etc.) you are reading and for evaluating its relevance and usefulness to your topic and your research process in general.
1. Authorship
2. Currency
5. References to Other Sources
6. Relevance to Topic and Assignment
7. Format, Organization, Appearance
Image: George Williams. Finding, Evaluating, and Using Sources, 2009. Flickr Creative Commons. 30 August 2010.