Listen to the problem. Make sure you are answering the question that you have been asked.
Begin by setting a structure. Think of four to five sub-questions that you need to answer before you can address the overall issue.
Stay organized. When discussing a specific issue, remember why you are discussing it and where it fits into the overall problem.
Communicate your train of thought clearly. If you have considered some alternatives and rejected them, tell the interviewer what and why.
Step back periodically. Summarize what you have learned and what the implications appear to be.
Ask for additional information when you need it. But make sure that the interviewer knows why you need the information.
Watch for cues from the interviewer. Any information given to you by an interviewer is meant to help you—listen carefully and follow their lead.
Be comfortable with numbers. You will almost always have to work with numbers in a case. This requires comfort with basic arithmetic and sometimes large quantities. You may also be asked to perform estimations.
Don’t fixate on "cracking the case." It is much more important to demonstrate a logical thought process than to arrive at the solution.
Use business judgment and common sense.
Relax and enjoy the process. Think of the interviewer as a teammate in a problem-solving process and the case as a real client problem that you need to explore and then solve. Our clients need pragmatic solutions that they can act on as soon as possible. Always focus on actionable recommendations, even though sometimes they may not be the most elegant solution to the problem.
Some common mistakes
Misunderstanding the question or answering the wrong question.
Proceeding in a haphazard fashion. For example, not identifying the major issues that need to be examined or jumping from one issue to another without outlining your overall approach.
Asking a barrage of questions without explaining to the interviewer why you need the information.
Force-fitting familiar business frameworks to every case question, whether they are relevant or not, or misapplying a relevant business framework that you do not really understand, rather than simply using common sense.
Failing to synthesize a point of view. Even if you don’t have time to talk through all the key issues, be sure to synthesize a point of view based on where you ended up.
Not asking for help. Some candidates feel it is inappropriate to ask for help when they are stuck. Whether it is a misunderstanding related to the overall problem, or whether you are struggling with a specific analysis, be sure to ask for help when you need it.