This is a selfish post. I want to record my notes of what I’ve learned on my current project so I don’t forget them, and so I can access them anywhere. Other video hobbyists might benefit.
This is almost exclusively theory, so it should be applicable to any video editing software/equipment you find. But as far as specific tips for helping Premiere… I doubt there’ll be anything directly applicable.

You rarely see transitions in professional documentaries. Those you do see tend to be very soft transitions, not the eye-popping ones. Save those for sporting events or commercials. MTV may or may not make good use of the eye-catching ones; I haven’t watched MTV in 10 years so I wouldn’t know what’s happening out on the edge.

Going from video to video tends to be a hard change with no transition unless the video segments are very similar. The other place you often see transitions is when changing media; say, from a B&W line drawing to a color photo or video. The more dramatic the change, the more likely you are to see a transition.

If you don’t have video to go with a segment of audio you have, find or take still shots and pan and zoom them. You can get away with showing the same image in a zoom for 30 seconds-plus, and by concentrating on certain elements of the image, the result can be dramatic–sometimes more dramatic than video would be. So you can match up a minute of audio of someone talking about a person long since deceased with a couple of still photos without losing your audience.

With a 640×480 image, you can get away with a 2x zoom on TV but rarely much more. Scanned shots or shots taken with multi-megapixel digital cameras will easily let you get away with a 4x zoom or more. Remember, DVD and miniDV are 720×480. VCD is 320×240; VHS is somewhere in between.

Use relevant sound effects to highlight the words your subject is saying. In addition to conveying atmosphere, they tend to heighten the senses and cover up the background noise that inevitably sneaks into your footage.

Get a $100 digital voice recorder. Take your subject into a quiet room and have the subject talk for a minute or two, then dump the audio to your PC for editing. With video editing software, a digital voice recorder and a digital camera, you can very quickly make “videos” that are a few minutes long that will be much more powerful than a PowerPoint presentation, and it’ll probably take less time.

Imagine giving a relative a copy of his/her life’s story, told in old photographs and/or home movies, narrated by their closest friends!

A camcorder can do double-duty for recording vocals in a pinch, but unless you can hook up an external microphone to the camcorder, a digital recorder with no moving parts is preferable. It eliminates the sound of motors and tape hiss.