I just finished writing a scene where a television news report was playing in the background and it reminded me how hard it is to get these moments right. Unless you’re literally having the characters stare at the TV set, you’re basically dividing the audience’s attention between two planes of information. If you don’t do it carefully, the audience won’t know where to look, and the scene will be a disaster.
Off the top of my head, here are four (hopefully) helpful guidelines:
The TV can only tell you one thing. It can say the big snowstorm is coming, but it can’t also say that mobster Carmine DeSomethingorother has escaped from custody.
Use the naturally empty moments of the scene. If there’s information that’s important for the audience, but not necessarily the characters, start on the TV and let the characters enter the scene where it’s playing. If a character’s waiting on hold, or is looking for dijon mustard in the fridge, that’s another moment you could cut to the TV.
Get the rhythm right. TV news in particular has a cadence, and you can’t just shove your exposition in to make it fit. Always think how the reporter would actually report the story and balance his goals with your goals.
Don’t make it too convenient. Don’t have a character flip on the TV, only to find exactly the story about them — unless it really is reasonable that there’s 24-hour coverage about the situation. Perhaps the only thing worse than this cliché is when a character rushes in, saying, “You’ve got to see this!” before grabbing the remote.
On the whole though, it’s amazing how little television people watch in movies as opposed to real life.