I prepared by brainstorming answers to potential interview questions (I got my list here:
http://forums.studentdoctor.net/threads/ultimate-potential-interview-question-list.719760/). I just wrote down bullet points for each question, rather then writing out an actual answer, and after I was finished didn't really reference the document again. You don't want your answers to appear rehearsed. I also did research on career options for pharmacists. I've been a pharmacy technician for 4 years so while I'm quite familiar with some aspects of pharmacy, in particular community, I wasn't as acquainted with other areas, and was surprised to find out about career options of pharmacists I had never even considered. APhA's website has some really detailed career profiles that would be really useful to you.
http://www.pharmacist.com/career-option-profiles. They also have a quiz to help you start thinking about what areas of pharmacy might be a good fit for you.
http://www.pharmacist.com/pathway_survey. I took the quiz and found some surprising results that I'm definitely going to see if I can get exposure to during pharmacy school. I would also do extensive research on the school your are interviewing at. Read their website in detail. Find out what about the program makes them unique. Are they working on some interesting research? Do they have a duel degree program that appeals to you? Unique experiential opportunities? Do your homework so you can confidently answer the question "Why this school?" because I can guarantee it will come up.
I would also make sure you're up to date on any current events/controversial topics that are currently circulating the news media. A few key examples would be the Disneyland measles outbreak/anti-vaccination movement, right to die laws (Brittany Maynard), Obamacare tax penalties, etc... Even though they may not ask you a question directly about current events, being informed and up to date on the big issues surrounding the medical field can be a great point of reference if the opportunity comes up. I've been able to reference the current measles outbreak during a number of my interviews.
Keep in mind some questions to ask the interviewer at the end, such as what research are they doing currently, leadership opportunities, etc... Pay attention to your interviewer.
Most importantly, relax and be yourself. Most of my one on one interviews progressed naturally into a conversation, which made the process way less stressful. The purpose of the interview is for the school to get to know you a little better beyond what you present on paper.
Pretty sure that messed up my confidence level somewhat.
