Lots of people obsessively practice case interviews for years. That's cool, but I wasn't quite that prepared—I had read several books, practiced starting dozens of cases online, and read lots of articles, but had only practiced one live case before my first phone interview. I had put quite a bit of time into crafting a cover letter and resume, and I knew all the common case frameworks.
I think there's a sweet spot of practicing cases where you have a solid understanding of the fundamentals but are still able to creatively combine frameworks.
Each of the 5 cases I encountered in the interview process at Bain included a question about framing, some simple math, and summarizing my recommendations at the end. No one was trying to trick me, it felt like a collaborative process, and a few were kinda fun! (my favorite involved plant-based bacon)
First, the process I used:
Articles from Crafting Cases:
These articles cover it all:
You should have a great answer prepared for "Tell me about yourself" (often the only question I was asked before jumping into cases), "Why consulting?" and "Why (insert company)?" All should have reasons and anecdotes that aren't obvious from your resume. But know that the majority of your interviews will be case-based, so don't be surprised if you get asked no personal questions.
Hopefully this is helpful... Good luck, I believe in you!