This is a great question. And too big to be answered via Tweets alone. Here are a few tips.
You can have a great novel without an antagonist (e.g. James Joyce’s ULYSSES—or the first two-thirds of MOBY DICK). But the vast majority of TV episodes require an antagonist. There must be a fight between a protagonist and an antagonist.
Plotting for a TV or feature film script must be very economical, because there are so many fewer pages than in a novel. This means you need to be very aware of the principals of story-breaking: plot, suspense and three-act structure. (As it happens I teach this.)
Also, in TV and movies, the protagonist must have a best friend or closest associate—so that he’ll have someone to talk to. Otherwise you won’t know what he or she is thinking! 🙂
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