General

(1) Use two or more cameras if possible, and cut together footage from each of them in post;
(2) mount the camera(s) on (a) tripod(s);
(3) make sure that the scene is well lit (ordinary indoor lights are only as fraction as bright as daylight, but daylight can introduce deep shadows; think about lighting carefully; consider the use of reflectors);
(4) if the video is to have sound, use a separate microphone attached to (one of) the camera(s) of reasonable quality - an electret/condenser microphone is highly preferable to a dynamic microphone; and
(5) if possible, fix the cameras' exposure and focus at the outset so that they do not refocus or change the brightness of the scene over time.

I hope that that helps!

Oh dear. I am, I suppose, a not doing things by halves sort of person. The others are right that you can get perfectly decent video footage by somewhat simpler means; the single most important thing, though, is good lighting: plenty of it, and preferably from more than one direction.

The best videos have good narrative.

Say something interesting!