Once you have agreed on a short list of schools to visit, you must call and make arrangements for The Interview. Typically, this will take place while you visit the school. What is involved?
Almost every school wants to meet candidates for admission. The admissions test scores, teacher, principal, extracurricular recommendations, and the applicant's essay and parent's statement all offer a snapshot of an applicant at a particular time and place. Conversely, the interview gives the admissions staff a chance to fill in the missing elements and assess the applicant's character.
Schedule well in advance.
Be sure to schedule your interview and school visit well in advance. Do not do this on a Friday afternoon, expecting to turn up the next day. There are only so many hours a day with limited interview appointments. If possible, get your interview out of the way by the end of November. Most applications, including the interview, need to be completed by the deadline.
What does the interview entail?
How long is the interview? It's usually about 20 minutes. What will the admissions staff ask? The person who interviews you wants to get to know you. He already knows who you are and what you have accomplished. He will be looking to see what kind of person you are, how serious you are about your school work, what your hobbies are, and so on.
This video describes the interview process and how to prepare for it.