Zoom video conferencing (recommended) Note: If the prospect is uncomfortable on video, you can turn the video off and just capture the audio.
Telephone - make sure to record the call.
In person - make sure to capture video or audio. You can use one of these methods:
Hire a professional camera crew to visit the office of your customer (this will cost you approx. $2k, but it’s worth it if you can afford it and the customer is willing to help you).
Buy a camera and camera stand. Practice with this until you are comfortable. Then set this up and record the interview.
Use your cell phone to record the video, or audio, of the conversation.
