Too much of the gain effect will produce blurring trails behind whatever moves which may, or may not, work depending on what you re after. Low light will produce excessive grain in the image. Take the time to set up your shots before entering the scene. Draw diagrams of each scene and of important camera angles. This minimizes the redundancy of constant rewinding and fast forwarding when you edit the movie.
Meaningful footage is whatever tells the story, develops the characters or sets the tone.
Don t underestimate the value of on-sight improvisational dialogue between actors to reveal plot, narrative and character. A cutaway is a term to describe significant moments up to ten seconds or so in length that speak for themselves without necessarily using words, dialogue or sound. They can be inserted in post-production over the existing soundtrack and add variation to the flow of images. Remembering to shoot cutaways for every scene will alleviate significant stress in the editing room. These are all cinematic conventions that can be as easily applied to the video medium often to great effect.