A case study method of teaching and learning is being able to apply the theoretical aspects of business (marketing, human resources, accounting, etc) into a situation on a case by case basis. Cases, of course, vary from a simple problem to a complicated organizational disaster. What the facilitator is looking for is not the solution to the problem but how you get there. For instance, did you really come up with the real problem or is it just a symptom of the real problem and you are just merely scratching the surface? And there are several ways to do this (like the "5 why's?", "check-recheck", statistical methods) which you will learn. Anyway, once you have your theory then you present it in the proper format. Harvard, by the way doesn't do this all the time, only for certain tracks of study. They are mainly known for their name recognition. The methods of teaching are the same, the amount of publications their professors have, however, is different.
Its better to be on the ground wishing you were in the air than be in the air wishing you were on the ground. Fly safe!