Source Type: What kind of information is it and who is the author?
Is it a news article? An opinion piece? Op-eds are biased by definition. Who produced the content? A news organization? Or is it sponsored by a political group or corporation? What are the author's credentials? Does the content have an obvious political slant? One way to identify partisan or political leaning is to see whether the content points in a particular ideological direction, or would tend to reinforce the views of one party.
Works Cited: Who and what are the sources cited?
News content usually cite sources for the information provided. These are the people quoted, or the documents or reports or data being referred to. As you read, note who is being cited. Are they scholars or experts in their field? Are they affiliated with a political party or organization? If it’s a research study or data, what organization produced it? If there are no sources provided, it becomes difficult to evaluate the information, which is often the case with biased media.
Interpretation: What is the main point?
Most media content offers a thesis, or main point, of some kind. Evaluating whether something is reliable is to ask whether the main point makes sense, and whether the conclusions are supported by the works cited and supporting evidence. What conclusions are being drawn? Do they follow logically from what has been cited? Biased media may provide information and examples that look connected but don't really support the main point.
Completeness: Is something missing?
Most content should lead to more questions. An important step in being a critical thinker is to ask yourself what you don’t understand about a subject. Look back at the source. Did you miss something? Or was it not there? Biased media will tell you what to think. The purpose of news content is not just to share information. It's also to help you understand what's happening and encourage you to respond or take action.
Rosenstiel, Tom. "Six Questions That Will Tell You What Media to Trust." American Press Institute, 22 Oct. 2013, https://americanpressinstitute.org/six-critical-questions-can-use-evaluate-media-content/.