My biggest tip would be to know why you want to come to Einstein, especially as opposed to other NYC schools. I'm from out of state and got asked this, answered vaguely, and then got asked it again until my answer satisfied. Read over Einstein's website, talk about what you like about our curriculum and programs and why it would fit what kind of doctor you want to be. I spoke about the global health opportunities and how that really fit my interests, but there are any number of ways to do it. Maybe you come from an underrepresented background and love Einstein's dedication to equality. Maybe you want to serve a great and diverse community like the Bronx. Maybe you've heard about how the school is pass/fail and the students are so collaborative and what a great learning environment it becomes.
Other than that, try to act like a person and less like a robot. It's super hard at interviews, I know. This was my 6th and last interview and by that point I think I was so done with structured questions and just tried to be myself, which I think helped me. The interview day is really nice because it's the most relaxed one I've been to. The admissions staff is so nice, make sure you take advantage of them if you need anything. They don't have any specific interview day program where you sit in a room and get lectured at, which I liked. The school really speaks for itself without all that. I haven't heard of anyone in my class who had a bad experience interviewing here, so just be calm, curious, and real and you'll be fine. Ask your interviewer questions, they love to talk about themselves. Good luck!
On a side note: after sending an in the area email, I got an interview. So feel free to do that if you get an interview at another NYC school. I did interviews at Cornell and Einstein in 2 days.