One of the most important components in documentary film making is interviewing your subjects. They need to be well planned to be executed perfectly.
Planning effectively means that you need to contact your subjects in advance so that you can explain your story and how their input will fit into the agenda. Good planning also demands that you set up a suitable place and time for the interview and preparing questions that will reach your objectives efficiently.
You must never just show up without making them aware in advance and expect your subject to submit to your questions and cooperate with you effectively.
When initiating contact; you don’t need to provide every single detail of your topic. You just need to provide enough information to engage your subject enough for them to be prepared but not too much to generate a rehearsed response. The best responses are those that are spontaneous.
Your location and timing needs to be at a place with the least noise and distractions. It would be best if your subjects are at their usual and normal surroundings and make sure enough time it allotted so that enough time is taken up for setting up your tools.
Don’t rush through the interview, in fact plan ahead incase you need to make multiple visits especially if your interview takes place over time. But make sure your subject knows about this possibility before hand.
Time accordingly to the type of medium or interview you are conducting. For example TV report interviews need to be delivered quickly where else feature documentaries could afford you more time.
Most importantly never allow your interviews to go overboard. Plan how you want the interview to go and what you expect to gain so that your subject does not ramble some sort of prolonged monologue. No one appreciates it or have the patience to sit through this.