How to interview now with more text

Alternate sides of the camera you ask the questions from. Just keep switching sides every time you do an interview. When you edit you'll be able to cut between people on different sides of the frame instead of everyone stuck to the same side.

Ask open ended questions for interesting responses.

Do not ask any question that can be answered with a yes or no.

Train the people to restate the question or answer in a complete sentence. Instead of "yeah Dave totally does that" you'll get "Dave is totally the guy that screws around on his girlfriends". Much better.

Tape off or turn off your tally light so they don't know when you are recording.

Wrap the interview, tell them you are done, physically relax then compliment them on something they said or say "i though you were going to talk about x, thank god you didn't". The trick is, the camera is still recording.
Then they start talking in a super casual manner about all sorts of stuff in an amazingly relaxed tone. Some of the best clips ever come from that trick.

Also just start rolling at the beginning, before you say lets get started. It's not so much about tricking people into saying bad things, as it is about tricking them into being relaxed and themselves in front of the camera.

This is a stupid one, but listen. It's amazing how many don't listen, don't engage in a real conversation, and don't ask the follow-up question.

People often hint at stories that they won't volunteer on their own, but will willingly give up if you ask them directly.

Write your questions down. You don't need to stick to them, but at least you know where you came from and where you are going.

Look them in the eye and be interested.

Don't ever interrupt them.

Let silence hang. Often they will jump in and fill the silence in an effort to make things less uncomfortable.

Nod while talking to them, but don't say anything unless you need to. Their voice is important, not yours.

Always encourage them that they are giving the best interview ever.

If you aren't getting what you need, and you are trying to get something out of them, and you've been at it for awhile, and they are getting nervous, tell them to relax. They already gave you some great answers which now gives you the luxury of getting picky and more in depth. Lies, but it will make them feel comfortable.

There you go. That's over 1000 interviews for camera's worth of experience for you in a lowly, less travelled SA forum.