Where can I find non profit cases to practice? BCG gives a lot of them in interviews. Also, how should one approach such cases?
You should check out Bridgespan website. McKinsey site also has a case example on social sector.
Related BootCamp article(s)
Putting It into Practice
There are 2 quick ways to schedule case interview meetings on PrepLounge throughout the stages of skill development
Getting Up to Speed
In order to repeatedly demonstrate prerequisite skills under the pressure of a real case interview, you need to learn the basics and practice cases.