1. Take care of the basics. Black, navy, or gray pants or skirt suit. Minimal jewelry and makeup. If you wear a heel, make sure to bring a pair of flats as many interviews include a campus tour that may require quite a bit of walking.
2. Try to get a hotel close to campus or on campus. Practice getting to the interview location the day before you actually have to be there. You will likely be in an unfamiliar city and won’t have a real sense of traffic, etc. so you want to minimize any potential for getting lost or being late.
3. Practice for the interview by doing a mock interview with either some of your current faculty members or someone in your career services office.
4. Remember that you really are interviewing them just as much as they are interviewing you. Truthfully, if you have done your due diligence and applied for the programs that appear to be the best fit for you, you can be successful at any of them. It really comes down to where you will get the most support and have the best fit.
5. Remember that EVERYTHING is a part of the evaluation process. You should not assume that the social with the faculty or the lunch with the current graduate students is a chance for you to let your hair down. All of the information gathered from your entire visit is a chance for the department to make a decision about whether or not you will be a good fit.
6. Really explore the faculty profiles of the professors you think you want to work with and read some of the work they have published. Are you really interested in the work they are doing? These are the people you will be working tirelessly with for the next several years of your life. You want to be as sure as possible that you can stay engaged with the work. You also want to be able to talk intelligently during the interview about how you might want to add on to the work they have done or take it in a new direction.
7. Make sure that you either get an opportunity to speak with current graduate students during the interview or that you get contact information so that you can speak with them either before or after the interview. I would be incredibly hesitant to choose a program that did not allow you to speak with current students. And again, remember that sometimes current students have some weight in selecting the new class so ask all the questions you need but do not assume that you can be more casual with the current students.
8. As soon as you can after each interview, write down your impressions of the visit. You will likely be going on at least a few interviews and if you get multiple acceptances you want to have something you can use to help in the decision process. A few things you may want to note include: What did it feel like to be on campus? Could you see yourself being there? Did the faculty and current students seem happy to be there and engaged? Did you feel welcomed by the department? What kinds of things might make it less desirable to be there?