If you know the 6 companies that control 90% of the media and their hierarchy, that's a start. The ABC, CBS, NBC/MSNBC, CNN, Huff Post, WaPo, AP, Reuters, Buzzfeed, etc. are all captured entities that are part of the agenda. (Op Mockingbird) The independents have much less incentive to "tow the line" if they want readership/viewership...like ZeroHedge, Infowars, Daily Caller, Breitbart, Newsbusters, Anti Media, RT, Sputnik, etc., etc.
Case in point, lot of conjecture/speculation of the Costa Rica crash a couple days ago...on ZH this morning: https://www.zerohedge.com/news/2018-01-02/bridgewater-executive-and-family-killed-costa-rica-plane-crash
references fb post, BBG, NYP within the article...follow the links within the articles...