The first step is to develop a clear idea of the purpose of the interview, book an appropriate guest and research their background. Ask yourself:
Why are you interviewing this person?
Why are they interesting to your audience? (Do you know who your audience is?)
The CiW interviews (and similarly those for Scientists not the Science) I conducted were predominantly with scientists who had little or no experience of being interviewed. However most had plenty online about their research and background, and I made sure to read up as much as I could beforehand.
Because of the highly structured and short nature of the CiW interviews I also drafted a list of questions to ask, along the lines of:
I had these on to hand as a checklist, but didn’t just read them out - this can come across as stifled in the recording. I tended to modify their tone and language during the interview depending on the context and how the interview is going.
Having a plan helps me focus on what I want to achieve with an interview, and also makes sure I don’t miss any obvious audio I wanted to record – for example the interviewee introducing themselves. For the longer Scientists not the Science interviews my plan tends to include themes I want to talk about, rather than specific questions. Ultimately I’m having a conversation and want it to be as natural as possible, while at same time slowly steering it in a particular direction – this is tricky and I’m still practicing.