99% of clients misunderstand learning and practicing. At its essence, you cannot practice McKinsey cases until you learn McKinsey cases. Most candidates start of their case interview preparation by reaching out to colleagues and consultants to practice cases, not having gone through the learning steps. Without a good strategy of separating learning from practicing you will simply absorb what you hear in the practice sessions and none of that is designed to teach you how to do cases. You must separate the learning from the practicing.