I'd had a bad semester during my sophomore year & the interviewer asked me to discuss what happened that semester & what would keep that from happening again.
I read the other interview feedback to try to gauge what sort of questions they might ask, I wrote out answers to the questions & then practiced answering the questions w/my hubby.
What was the most difficult question?
see above -- but really, there weren't very many questions asked at all. It was just a real getting-to-know-you type of conversation.