Great that you want to structure your case prep!
The beautiful thing about consulting interview cases is that you basically don't need any industry specific knowledge. The toolkit that you build during the preparation should allow you to tackle any type of case in any industry.
I therefore truly believe - and I am sure there is not a single other coach here that would disagree - that starting your preparation with building industry specific knowledge is the wrong approach. It will probably even be counter-productive.
Think about the following situation: You're in the interview in an office in India and a consultant on a transfer from Norway presents you a case about the porta potty rental market in central Europe. Or the market for bottled water coolers in Southern US. Or the market for printed labels for CPG packaging. If you have built your preparation on industry-specific knowledge, you're gonna be thrown off track by this and never recover.
What you should do intead is focus on building the general toolkit. To do that, I recommend the following approach:
- Read up on the typical approaches and standard frameworks to get the concept. There are many books (Victor Chen, David Ohrvall and countless others)
- Then, do 3-4 cases to get a practical feeling for what a case is like. Start with easier ones - e.g. market size mini cases, simple profit tree cases, etc. This will help you develop a rudementary sense for how cases work. If you're still not comfortable, do 5-6 more until you get the hang of it.
- The next 5-6 cases should cover cases from all major types and help you gain the experience and comfort with standard frameworks and the thinking required for solving the cases.
- Lastly, you will want to do 4-5 cases to hone your skills. Practice with people who understand what they are doing - experienced interviewers, coaches, etc. that can give you 1-2 main items of feedback after each case that you can then practice to apply and improve on in the next case. During this time, you should also practice to move away from off-the-shelf frameworks and tailor, or - even better - develop your frameworks specifically during the case.
At the same time, start reading the Economist, Financial times, etc. Through this approach you will gain something much more powerful than industry-specific knowledge, and that is general business judgement. A deep understanding of how business works, what drives economies and how this will impact the case in front of you.
It will enable you to solve the European porta potty case I mentioned above and countless others, even if you've never heard about the industry.
If you need a coach along the line, especially for the last phase before the interviews (that is where coaches are most useful, see above), let me know!