Set the scene
A distant train, a wet railing, and a paper cup give the scene texture. Begin with what the characters can see, then let one odd detail interrupt the ordinary evening.
Choose what happens next
Decide together whether the sketch is a destination, a memory, or simply an unfinished drawing.
An opening to borrow
“There is one building in this skyline with no windows. What do you think happens inside?”
Make the scene yours
Choose a pace that suits you. Add one observation of your own rather than specifying every reply. The characters are fictional adults, and the setting can stay entirely invented. Keep personal addresses, private histories and identifying details out of the exchange.
A natural ending
The characters can put away the object, change their plan, or decide to stop for the day. You do not need an elaborate conclusion. A short scene is complete when you no longer want to add another turn.