Your protagonist has been asked to showcase a little-known, unusual talent at a community fair's talent contest. Begin on stage and show not only the performer but also the crowd's reaction to this talent unveiling.
There's a saying: "Everyone is the hero of his or her own story." For a 10-minute writing exercise, enter your book from another character's eyes. Think about how differently that character would experience your plot and capture that in a short story.
Your protagonist sits down at a desk and begins penning a letter to his or her younger self. What would they tell their past selves? What regrets do they voice? What lessons have they learned? How have they changed? Write this imagined note yourself, in your protagonist's voice.
Your protagonist has just been bequeathed $5 million dollars. The money came from an anonymous benefactor who wants your protagonist to donate all of it to five charities. How does your protagonist react? In a short story, write down what would happen next.