Billy Wilder's 10 tips for screenwriting

Billy Wilder was the director of many excellent movies, including Sunset Boulevard, Some Like It Hot,
and Double Indemnity. Here are 10 tips about moviemaking that he shared in the late 1990s with Cameron Crowe (Fast Times at Ridgemont High, Almost Famous, Jerry Maguire)
From Open Culture:
Wilder was 90 years old when the young director Cameron Crowe approached him in 1996 about playing a small role in Jerry Maguire. Wilder said no, but the two men formed a friendship. Over the next several years they talked extensively about filmmaking, and in 1999 Crowe published Conversations with Wilder. One of the book's highlights is a list of ten screenwriting tips by Wilder. 'I know a lot of people that have already Xeroxed that list and put it by their typewriter,' Crowe said in a 1999 NPR interview. 'And, you know, there's no better film school really than listening to what Billy Wilder says.'
Here are Wilder's ten rules of good filmmaking:
1: The audience is fickle.
2: Grab 'em by the throat and never let 'em go.
3: Develop a clean line of action for your leading character.
4: Know where you're going.
5: The more subtle and elegant you are in hiding your plot points, the better you are as a writer.
6: If you have a problem with the third act, the real problem is in the first act.
7: A tip from Lubitsch: Let the audience add up two plus two. They'll love you forever.
8: In doing voice-overs, be careful not to describe what the audience already sees. Add to what they're seeing.
9: The event that occurs at the second act curtain triggers the end of the movie.
10: The third act must build, build, build in tempo and action until the last event, and then -- that's it. Don't hang around.
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