This was the first video interview I conducted, and the first video I ever edited, so I am sure you can spot many mistakes. But some things I got right, even though in very rough form:
1. Use a tripod, and aim it so that the subject speaks to you. The interview becomes more of a conversation, allowing stories to flow. My aunt quickly forgot that the camera was on! I had tried interviewing relatives while holding the camera, which was a big mistake. Not only did the camera shake, but the interviewee remained self-conscious.
2. Include photos and old film footage in the video. If your interviewee refers to a person or address, it is helpful to your family story if you include photos or film footage to illustrate the story. Adding these items also provides a visual break and will hold the viewer's interest.