I'm an HR manager transitioning back into school to become an RN (I start next week!) ... here are my suggestions:
Be early (5 - 10 minutes or so).
Be gracious to whoever greets you (being rude to my receptionist will get you nowhere).
Present yourself well ... shake hands and make eye contact.
Clothing ... says everything! Dress conservatively with something that says you have personal style (a small piece of jewelry, small classic earrings, a beautiful ring, etc). Nice shoes and a nice handbag are a must. Scuffed shoes or an old purse tell me you don't care about how you look (and nurses should look professional).
Smile. Make eye contact continuously.
Think about your answers ... I'd rather have a moment of silence than hear you stumble through a sentence.
Really listen to what the interviewer is asking you ... if you seem distracted, I will feel put out.
Thank the interviewer more than once.
I guess that's all I can think of right now ... my head is not in HR but in Nursing right now!