BCG Real Life cases are 3 very short cases / business situations that you have to solve. The key difference - they are very time constrained (±10 min) and you don't have to do the full structure and follow through it.
The best way to prepare - prepare in the same way you would prepare for the regular case interviews. Also, since these cases are less about the initial framework and more about business sense, I would recommend paying a lot of attention to practicing the cases in various industries / functions:
- 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. 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).
- Every 10 cases revisit the previous cases and think how you would structure them differently now having the new experience and having solved the new types of cases
Good sources might be:
- Books - one good book about airlines with numbers and industry analysis can give you all needed industry knowledge
- Company reports, equity reports, etc - usually have a good overview of company and industries.One of the best sources to prepare
- HBS cases - quite useful, but not sure if lot's of them available publically. Probably worth buying