Hi there,
What exactly do you mean by "devleopment sector"? Can you name a few firms for us?
If they interview you in a case format, the difference in prep should not be large. You should be going through the same materials, etc., but just make sure to focus a bit more on the industry/functions that that company serves!
The case prep is the same. In addition, I would make sure to read a lot of stuff above and beyond. The cases mgiht add a critical lense on undesired side effects, best tools of implementation, etc. and that is something you can read from reports, evaluations, newspaper articles on similar projects.
