depends. you should research the type of nursing the clinical area provides and start looking into best practice, policy directives and ward philosophies etc. to get the technical questions out the way. as for yourself - be honest. descrobe your strengths and your weaknesses but also that you are willing to learn and need a safe, nurturing environment in which to develop your clinical skills post uni.
it was easy for me as i had a second year placement where i took my first post and had done agency hcsw work there too, so badgered them into giving me a job and knew the place like the back of my hand. at the end of the day, research as much as possible, line up other interviews (just in case!) and they do not expect you to know loads as you just qualified. also, if you don't know the answer to a question or don't understand it - say so. nothing looks worse than a fudger! it's really not that bad...good luck!