No when or where
True stories happen at a time and a place. Fake ones float in space.
Think about telling a friend what happened at recess. You say when (today), where (the big field), and who was there.
News works the same way. It tells you the day, the city, the school, or the country. Those details let other people check the story.
When a story has no time and no place, it can be copied and shared forever, and nobody can prove it ever happened.
Spot it
“A boy found a dinosaur egg in his backyard and it hatched!”
What boy? What town? What year? Without those, there is nothing to look up.
Detective move
Hunt for the when and the where. If you cannot find them, keep your "maybe" hat on.