If there’s one simple thing that you can do today to make your cinematography look more professional and polished, it’s incorporating practical lights into your scenes.
Practical lights are, of course, traditionally defined as any light where the source is in frame. More often than not, this means lights that are built into your locations (usually ceiling fixtures), desk and floor lamps, televisions, computers, and strings of Christmas lights. It can also refer to headlights from a car and street lamps. All sorts of things can be used as practical light.
Before we get into the specifics of why and how to light with practicals, here’s a quick quote from Roger Deakins, taken from his fantastic online forum, about the importance of practical lighting, especially in the digital age where camera sensitivity and dynamic range are through the roof: