You want to make eye contact while you are simultaneously able to see and react to the person you are talking to. I find that it helps to place the image of the person you're talking to near the camera. For a good example of what to do, watch how newscasters present themselves on screen. If you are unused to being on screen, practice a mock interview with someone in your kitchen cabinet and have them record you. That way you can iron out any flaws prior to your first interview. Good luck!