in general, if you ask the right clarifying questions at the beginning, you should be able to crack cases even for unfamiliar industries. Having said that, previous knowledge of a sector can for sure be useful to improve business acumen. In order to improve your knowledge of specific industries, I would suggest proceeding as follows:
- As a starting point I would try to collect all the banking/oil and gas type of cases available online in MBA handbooks.
- I would then move to solve them, adding to your structure the elements you may have missed due to lack of industry knowledge.
- I would complete the knowledge on the industry googling recent information on them
- In case you need to develop additional knowledge, you can move to specific books or equity research reports. Understand how to ask the right questions at the beginning is usually more useful though.