How do you answer 'Market yourself' in a job interview?

By the time they start asking questions, they have already decided.

Studies have shown that people make snap decisions about the interviewee based on the first 27 seconds of the encounter. Their attitude becomes:

"Well, of course they didn't know the answer."

or

"Well, that was a really hard question."

So, smile, dress nicely, and act with confidence. Don't be arrogant, but remember that you are interviewing them as well.