Skim the articles on your group page. Look for patterns in language, and ask yourself how the authors demonstrate how they know what they're reporting is true.
It's a good idea to keep up with what's going on the the major networks like NBC, Fox, and CNN, as well as big name papers like the New York Times, Washington Post, and Wall Street Journal
Additionally, sources like Propublica, the Center for Public Integrity, and the Center for Investigative Reporting are excellent outlets to follow for in-depth, investigative journalism. Buzzfeed, although known for viral videos and just-for-fun quizzes, is also doing some high quality investigative journalism in its news wing.
The list below also highlights some high quality news outlets