Get a sense of their pacing and style beforehand. I love You Tube for this. You know what it’s like. The moment you see someone move and speak you get that instant feeling of what they are about. It helps you break the ice much faster when it comes to the interview as you are no longer trying to work out who they are for the first few minutes. Listen to other podcasts they appeared on too. What points did your guest raise that you think were not covered properly?