Hi,
Focus on the most common industries in the following priority (sorted by probability of getting a case): 1-retail and CPG; 2-airlines; 3-Telecom; 4-banking; 5-natural resources; 6-tech
There are several sources of info to develop business sense:
1) Cases - you simply solve 50-70 cases and get a broad knowledge of different industries, common pitfalls and questions. The key here - find good partners who already had case interviews with MBB companies
2) Company reports, equity reports, IB roadshow docs - usually have a good overview of company and industries. The most useful source!!!
3) HBS cases - quite useful, but not sure if lot's of them available publically. Probably worth buying
4) Books - one good book about airlines with numbers and industry analysis can give you all needed industry knowledge
5) News, Industry blogs
For each industry, you should understand:
- Revenue streams
- Cost structure
- Margins
- Key performance indicators
- Key revenue drivers
- Industry trends
I strongly recommend practice drawing structures for each industry - profitability, value chain, etc
Then I will switch to getting functional knowledge and key concepts in:
- Marketing (Brand and trade marketing tools, etc)
- Supply chain (Ops metrics like cycle time and throughput time, distribution and delivery specifics, etc)
- Finance (Basic Accounting and Valuation)
Good Luck