Peter Woit assembles some information on the role of the New York Times and the rest of the main stream media in trashing Hillary Clinton's reputation here.
Arun Gupta, from whom I got the link above, assembles some information on the motivation of the media, including this quote from the head of CBS:
CBS CEO Les Moonves (February 29, 2016):
Les Moonves, the chief executive of CBS, celebrated Donald Trump’s candidacy for the second time on Monday, calling it “good for us economically.”
Moonves, speaking at the Morgan Stanley Technology, Media, and Telecom Conference at the Park Hotel in San Francisco, described the “circus” of a presidential campaign and the flow of political advertising dollars, and stated that it “may not be good for America, but it’s damn good for CBS, that’s all I got to say.”
“So what can I say? The money’s rolling in, this is fun,” Moonves continued, observing that the debates had attracted record audiences.
The CBS media executive also riffed briefly about the type of campaign advertising spending produced by such a negative presidential campaign. “They’re not even talking about issues. They’re throwing bombs at each other and I think the advertising reflects that.” Moonves added, “I’ve never seen anything like this and this is going to be a very good year for us. … It’s a terrible thing to say, but bring it on, Donald, go ahead, keep going.”