... the source is reputable. What can you learn about the site or publication?
... the motive is clear and objective. Why did the author to write and publish this information? Compare to other sources to help uncover biases.
... the author is an expert in an appropriate field of study. What qualifies the author(s) to write about this subject?
... it has been examined by other researchers (i.e., it was peer-reviewed) or editors.
... claims are supported by evidence and facts are sourced. Read carefully. Is this a summary or in-depth examination of the subject? What is the claim? What evidence is used to support the claim? Track down sources of evidence to determine authenticity and reliability. Compare references to those in other sources for quantity and quality.
... it can be corroborated. Can you verify information in different sources?