How do I prepare for a Cambridge interview?

In reality, there is very little that can be done to prepare yourself. The point of the interview is to allow the interviewers to get to know you and decide whether you would be a good fit to the Cambridge course. The interviewers will deliberately ask questions they think you won't have prepared for, because that is what learning is like, and they want to know how you learn.The best preparation is to eat well and get a good night's sleep before the interview, and try to keep from getting too nervous (though this is understandably hard). The interview is as much for you as for the interviewers: while they're deciding whether to accept you, you can also decide whether you would accept an offer if you got one.