This is a nice little compendium at WikiHow: How to Recognize Bias in a Newspaper Article. It applies to other news/information than just newspapers, of course, including TV news and Internet news. Scare quotes, unsourced statistics, selective time frames for comparison, missing facts, use of labels or emotionally-charged jargon, etc., it’s all here. Should be required reading in civics classes (if anyone teaches civics any more).
The one element that’s at all questionable is item #11:
Look for at least two sides to every story. A good reporter will allocate adequate space in the story to present facts and figures supporting all sides of an issue. Ask yourself if all sides of this argument or dispute would agree that their views were represented fairly? If not, the story may show bias.
On the one hand, and on the face of it, that’s hard to argue with. And one-sided articles are often a good warning flag of bias.
On the other hand, not all sources, or sides, are created equal. In a science article on the origins of the moon, discussions with astrophysicists and selenologists and the like are probably of more value than interviewing Rev. Fred Firkins who thinks the Moon was shot up into the sky by Atlanteans as a time capsule for their civilization, which NASA already knows but is keeping secret. Firkins has an alternative viewpoint, but a good journalist will exercise some judgment in considering how credible it may be. Ignoring alternative views may be unfair and biased — but treating them as the same as other viewpoints is equally misleading, if not more. And, yes, the same applies to arguments about evolution vs. creationism.
Which in turn reminds me of this article by Amanda Gefter. It focuses on how to detect “a hidden religious agenda” in scientific articles, and there’s not an observation it makes that doesn’t sound spot-on. Well worth reading — though you can’t read it at The New Scientist, where it was originally published, because it got yanked from the web after mysterious “complaints” (rumor being that some creationists threatened to sue for libel, though there’s nothing there that strikes me as libelous).
Which, I suppose, makes the point.