Identify and explain two ways in which the media have contributed to candidate centered presidential campaigns
One of the biggest things is that the media spends so much time and resources looking at the candidates and trying to bring up any past indiscretions that can be exploited. By doing this it takes the focus away from the issues and puts it directly on the candidate.
I think that you should look at the way that the media focuses on the "horse race" aspect of political campaigns. The media just looks at who's winning -- who's getting ahead in the polls, who's dropping down. They don't look at the candidates actual policies and such. This encourages a focus on the candidates rather than on their policies or ideas.
The first way I feel the media has turned elections into more candidate-centered events, as opposed to issue-oriented ones, is they ceaselessly investigate and report on every aspect of a candidate's life, even from the time they were little kids. If there is the mere appearance of wrongdoing, the media will repeat the allegations endlessly until it doesn't matter if it's true or not. In my opinion, this keeps some very good people from running for the office.
The second way I can think of is how the media plays the "gotcha" game so well. In search of ratings, they would much rather have drama-inspired arguments and tit-for-tat spats between candidates, and repeat the one liners as if they were actual news. This has made it so it seems as though being quick on your feet, with a good sense of humor and quick catchphrases is more important than having executive skills or a grasp of the issues.
Both examples show the media focusing more on a candidate's image as opposed to their presidential timber.