So how do you look your best when you're interviewing someone because the camera can be on you or you can certainly take cutaway shots of you. You need to be looking at the person as often as possible looking intently looking like you're interested and nodding occasionally not because you agree with the person, but to make the person realize I'm here, I'm listening. I understand, continue. beyond that. It's not that much different than when you're talking directly into the camera. I would recommend when you're interviewing someone, look at that person.
If you then want to introduce that person to the studio or to the camera, do that and when you're concluding you can but otherwise, look at the person when you're speaking to them. Try to make it seem like a real conversation and have all the natural movements who would when you are relaxed, do that, and you'll be in good shape.