I've gone through tours/interviews and phone interviews, no official interview yet. That's coming up this Friday. But I feel like it's fairly straightforward.
1. I would definitely have copies of your resume, most letters of recommendation are private and confidential so I don't have copies of those. I would also bring written out questions for them, along with written answers, if that works for you. It could help to have something to go off of, or at least practice with. I've found writing out answers to standard interview questions helps me know what to say, and having it in front of me can help guide me if I get stuck. Having questions prepared for them is professional and can help prevent you from forgetting important questions or blanking from nerves.
2. I am also female; I've always worn suit pants/slacks. I would think a tasteful skirt of appropriate length could be acceptable as well, but I feel more comfortable in slacks myself.
3. This website: http://www.gradschoolheaven.com/grad-school-interview-questions.htmlhas a LOT of the questions I've come across during interviews so far. I would follow some of the guidelines on the website. I can't think of any specific don'ts... don't ramble, don't talk too long, that's all prevented by planning your answer. Pause if you need time to think. Be honest and speak from the heart... most of these questions I just have honest answers to, I don't need to "plan". I KNOW what I want to study, why I like the university, etc. I KNOW why I got into audiology, I don't really have to "plan" those answers.
4. I would send thank-you emails, yes. Just something short and sweet. It can't ever hurt, I did thank you emails after my tours as well; the more contact you have the more of an impression you make!
I wouldn't worry too much. As long as you're sure of yourself, your passion and desire to be an audiologist, just type out your answers to the questions listed on the website and you should be fine . And bring questions for them! I would say it is definitely safe to ask questions about when you should expect to hear about acceptance/funding, maybe what they see as a high quality candidate, or specific questions about aspects of their program that are important to you. You can ask about specific research projects you're interested in and how you can become involved, etc. Just relax, take a deep breath, and be excited to be there and show them who you are and how you would make an awesome candidate and addition to their program. But remember, you're also interviewing them. See them as peers whose program and opportunities you are also evaluating. You are going to be fine!!
Just curious, where are your interviews at? Mine is Friday at University of Iowa