Best Practice Strategy/Resources
1) Practice in RocketBlocks
2) Practice in casebooks. LabCo and Enerforce are two of my favorite chart-based cases.
3) Read the Economist (especially the graphic detail)
4) Ask case partners to focus particularly on your chart-reading skills (i.e. by providing you with cases with many charts) - Bain and Deloitte cases tend to be chart heavy
5) Get a coach. For example, I run a number of exhibit/chart interpretation training programs for other academies/learning centers. Feel free to reach out to get the same training!
In terms of being able to interpret charts/graphs effectively
1) Read the title - and understand it
2) Read the legends - and understand them
3) Remind yourself of the objective / hypothesis in the case, to see where this might fit
4) Find the differences - where does the line graph plummet or spike? Which column is a lot smaller or bigger than the others? Where does change occur? The differences are what matter
5) Talk outloud while interpreting - first, it helps you think and process your thoughts, second, it lets the interviewer provide guidance and course correct if needed.