I agree that looking at some standard interview questions is helpful as is preparing a few questions about the school that she can ask about. Firm handshake is good advice as well. Most important thing is to be herself, let her interest in the school shine through and make sure they know that while she appreciates the scholarship she was already awarded, that having this scholarship will make a difference in her final decision.
One additional suggestion…when my D went to interviews, she brought a couple of copies of her resume in a folder with her. If your D has one prepared, I’d have her bring it and offer it to the person conducting the interview. My D felt that having the resume allowed for a better conversation as the interviewer could target questions to her interests/activities and she could talk about things she was very comfortable with.
Not sure if these are tips, watchouts, or just advice based on my experience as an interviewer… but I hope this is helpful. IMO, there are interviewers who want to extract new, differentiating information and interviewers who want to gauge the “fit” more subjectively. The best try to do both. I agree that eye contact, a big smile, and a confident handshake make a great first impression. So does body language. Don’t slump in your chair or look/act lethargic; sit on the edge of your seat, be attentive and alert, and let your body language communicate your enthusiastic interest. Then, listen. It is at least as important to get an accurate read on what each question is really asking as it is to jump in and answer. Don’t be afraid to say, “That’s a great question” and take a minute to compose your thoughts. Even ask for clarification (e.g. “Are you wanting to hear more about my internship responsibilities or what I learned from the experience?”). At the end of the interview, ask “Have I answered all your questions completely?” and wait for confirmation. Then, finish as strong as you started – with a big smile, firm handshake, and sincere “thank you for this opportunity.” If it feels right, consider adding, “I’m even more excited about my future here than I was before this interview.” If you mean it and they can tell, it could well clinch the offer.