Rule of Thirds
Reason: Aligning your subject or horizon to 1/3 of the framing feels more natural and less intrusive. It makes your audience feel like an observer, like a fly on the wall.
Exception: Centering your subject to make it imposing and powerful. Also center your talent if he or she will be speaking directly to your audience.
Reason: Keeping the camera at eye level makes the audience feel equal with the subject.
Exception: Raising and lowering the camera conveys superiority or inferiority, respectively. Just slightly raising the camera can also hide the chin and bring out jawline.
Reason: Zooming out minimizes any shakiness and out of focus footage.
Exception: Zooming in creates shallower depth of field to separate the subject from the background, which is ideal for portrait so long as your camera is stabilized (i.e. on a tripod).
Light Source Behind You
Reason: Keeping the light source behind you means the light will face the subject.
Exception: Sometimes light can be too harsh (like high noon on a sunny day) in which case you can try bouncing the light or shooting against a diffused background. You should also shoot against the light for silhouettes and confidential shots.
180 degree rule
Reason: Keeping the camera(s) on one side of the subjects is ideal for cutting back and forth between two shots because the subject will be facing opposite sides like they are talk to each other.
Exception: Consider breaking this rule when you want to introduce confusion to the scene. Sometimes, the space simply does not allow for such a setup. In which case you may be able to get away with flopping the shot in post so long as there are no dead giveaways like text.
Which rules do you follow and which ones do you break? Love to hear your thoughts, please comment below.