How should I prepare for a research assistant interview as a cs undergrad? I've reached out to a few professors and received responses.
I'm pretty used to going to interviews for industry jobs but this is new and I feel like I have no idea what I should talk about. I'm a second year cs student.

So far, i've read 2 or 3 of their most recent research works and have a good idea of what they want to do in the future. I also have a pretty general understanding of their fields although some areas do seem to be out of my league. 

What are good questions to ask a professor about their research? 
Are there common mistakes students make when approaching an interview such as this one? 
How do these interviews typically go?
From my experience, the academic setting is more relaxed on the interview. The interview I had for my GRA position had very few knowledge based questions. They want to see that you are highly enthusiastic about your domain of research, and that you're eager to learn.

If you have industry experience that is a huge plus! It shows you can actually work. I think one of the biggest fears of the lab director is a GRA/RA that is not able to accomplish much, i.e. losses motivation. Your industry interview will be more nit-picky about experience in a specific domain.

Being a GRA/RA is not like a course where you are told what to learn and when to learn it. You will be challenged to motivate yourself to solve research problems on your own time. It can be harder than industry in some ways, because you are given more conceptual work with no 9:00am to 5:00pm schedule to keep you active and focused.

I would focus more on touting your academic accomplishments. This assures them that you can handle a full course-load and research concurrently. I told them that I could not see myself working anywhere else, and that this line of research is the most meaningful thing I could be doing with my life. I didn't have to prepare that, because I meant it.

If you really what to know what the interview is like you can: (1) look online on Glassdoor or Reddit, (2) ask someone who is already in the lab what the interview is like.