Hello!
I've finished two interviews and I am an international student as well, so my experience may of some help, I suppose:D The first one seemed like a language test since they didn't ask too many discipline-related questions. I was nervous, though... It went smoothly because the faculty was very considerate and patient. The second one was tense! A lot of professional questions related to my work and inspirations. I tried my best to say everything that came up to me, while there are some points that I don't think I've made them clear. What I think is we need to relax. Show them everything we've got and it'll be fine ? Good luck!