On the day of your face to face interview, first impressions matter. Speak confidently and try to be comfortable. Keep a bottle of water handy. Smile :) It's easy to say but i understand it can be nerve-raking! That is why preparation is the key. The obvious place to start preparing is by looking at the Job Description (JD). What about the internship caught your eye? Any particular point? Was the JD clear and got you excited to apply for the role? Or was it your favourite company? What about the company do you like?
Talk about the above points and also the skills you have to offer and how that is a fit.
Tech skills - have you submitted any white papers? taken any additional online course/s?
Non Tech skills - It's also a time to talk about what extra curricular activities you have been involved in and see if you can tie that to the role. E.g if you are a part of a student committee and involved in organizing events, or leading them, or an editor of a college magazine, these talk about your inter-personal skills. These are your strengths and shows collaboration.
The interview process is as much about you getting to know them as they getting to know you. So have a list of questions for them too. E.g. what would a typical intern's day look like at your company? How do your team members unwind? What according to the interviewer is the best part about working at the company?
Always ask what the next steps of the interview are and don't forget to follow up. It's important for you to have a realistic understanding of the interview timelines.
Hope these help. Good luck!