I applied for a grad scheme in the civil service and for the interview, they gave me time to prepare examples of e.g., team work, overcoming difficulties? etc. and within these areas, they then asked lots more specific questions. One thing I remember was when they said "give an example of when you tried something new/learnt a new skill", I told them about learning Chinese, and when I got my evaluation back, it said something like "shows no interest in personal development"...which is WAY off the mark! I didn't get the job, clearly!
So... I would recommend preparing for competency based questions, and make sure they're good ones!