Given that I'm still a nursing student, I can't give you pointers on the interview content, but as a former recruiter in HR, I can definitely give you a few simple tips for the actual interview.
At the beginning of the interview, use the DONs name as you shake their hand and maintain good eye contact.
During the interview, mimic their body language. If they are relaxed in their chair, don't sit rigidly in yours. If they throw a question at you that stumps you a bit, avoid "Ummmms" if you can. Instead replace them with phrases like, "That's a really great question and I believe..." You buy yourself time to think about the question while still sounding eloquent.
At the end of the interview, if they stand up, shake your hand and have you show yourself out, instead of just walking out, open the door, stop, turn around while standing in the door frame with a big smile and thank them for their time using their name. This one may sound a little silly, but it's the difference between their last image of you being your behind walking away, or you with a big smile framed in the doorway.
Sorry I can't be of more help with the content, but hopefully this helps a bit. If you go in with confidence and stay relaxed, I'm sure you'll nail it. Good luck to you!