Lots of good advice, there, @h8nnah. And as someone who does interviews for his alma mater, I’ll add that students should keep in mind that in most cases the interview doesn’t carry a lot of weight in the decision to admit a student. Yes, in some instances it can help or hurt a student’s chances a bit, especially if the student is a borderline case. But unless the interview yields important information that wasn’t included in (or wasn’t apparent from) the student’s application, the interview probably won’t be thing that gets a student accepted or rejected.*
Given all that, there’s really no point in getting overly stressed about an interview. Students should take the interview seriously, but should remember that interviews are two-way auditions (students want the school to admit them, but the school wants to convince the students that they should come if admitted). So yes, come with questions, and be prepared to discuss the school and what you think of it.
*For example, I know of a case many years ago in which a excellent student was nearly rejected from an Ivy because of a dip in her grades. It came out during her alumni interview that her mother had cancer and the applicant had been running the family’s household. The young woman hadn’t mentioned this in her application, nor had her high school guidance counselor noted it in her letter of recommendation. The university accepted the young woman after learning of her situation. (I heard this story directly from the university’s dean of admissions.)