Sorry, I meant interviewee. Fixed title.
You know, for a lot of schools I applied to for UG, I was interviewed by a current student. You might benefit from trying to join such a team and see what makes an interview good, bad, horrible, cliche, clever, overly-rehearsed, boring, what-have-you, yourself. If it's late for that I have some general advice.
1. Be yourself, but be the absolute best version of yourself
2. Think about your values and the kind of person you want to be. I'm very neurotic naturally, but I want to be easy-going so I've been working on that and hope it would come across in my interviews
3. Preparation. You shouldn't be surprised by the dress code, MMI format, or bioethical terms. You shouldn't act like you've never considered an answer to "what's your biggest weakness"
4. There's a difference between having prepared thoughts to questions and having an obviously rehearsed speech. Interviewers can hear it. You definitely want the first.
5. Awkward silence is better than 'likes' and 'umms'
6. Be positive! Be the kind of person the interviewer will want to spend time with in the future. "Yeah, that was hard but I worked harder and got a chance to prove myself and feel grateful that I could challenge myself" is infinitely better than "that was so hard and unfun and I barely got through it and I never want to do anything like that ever again"
7. Brag about yourself. But don't be entitled or arrogant. The difference is in tone, phrasing, posture, and if you are willing to talk about past and potential areas of growth
8. Plus points for questions, minus points for questions where the answer could be found on the internet.
9. Don't ramble! The conversation might not flow that naturally and there will be long pauses you'll want to fill in. Say things if that add to the discussion (that is, selling yourself as a good applicant), but otherwise, let them consider the next question they want to ask you (for job interviews, this is super relevant for phone interviews)
10. This is also more for job interviews but the principle applies: some jobs will give the receptionist and insta-veto on any interviewees. If you're mean to people you feel are 'beneath you,' they don't want you, regardless of your qualifications