Write about a character looking back at their childhood. The voice should clearly be that of an adult, and they should examine moments in their childhood with all the experience and perspective that comes with distance and time. The “occasion for the utterance” should be clear, too, meaning let the reader understand why the character has decided to reflect on a particular childhood experience. Perhaps the adult sees a lone monarch butterfly in a sea of green plant life and remembers when he was four and ate a butterfly. Maybe the adult is on jury duty for someone accused of robbery and she remembers being a little girl and swiping money from her mother’s purse.
Whatever the situation, keep the voice adult and draw parallels between the past and present. Give this exercise at least fifteen minutes of your time, though this is the sort of exercise that might demand more of your time to really get the story rolling.
Write it up and see what happens.
(this post was added retro-actively to assist continuity.)