During interviews, don't worry about solving the cases perfectly or even necessarily giving the right answer. Rather, you should focus on structuring your thinking and developing an organized approach to solving the problem.

You should also try to establish a dialogue with the interviewer and explain your thought process. By asking the interviewer questions, you can find out additional information to help you solve the case.

Another way to approach the interview is to think of it as a chance to get to know a McKinsey consultant — a potential colleague — and have an interesting discussion with him or her about a particular business problem.

The key is to be relaxed and not too worried about every little detail. Instead, focus on the overall impact of your conclusions.