What advice would you have for someone going to interview for an internship in music?

The normal elements of researching the company to have a good overview of their work, history and what they are doing now. If possible, look up the background of the person interviewing you and see if there are any common areas of connection.

But the biggest advice I can give is to show your genuine excitement for the opportunity. I have been in the hiring position for entertainment companies in the past and for me the biggest draws were to see that the person already had a history of studying in the field but also to gauge their level of interest for working hard and learning in the new company environment.

If you don't have genuine excitement for the opportunity then choose something else. Don't be cool. Be hungry to learn and open.

I would agree with the above comment, research the company, see if you have done anything that is similar to what they do.