A random short story can incorporate different time periods. It could start in the present day and then through some magical event, the character is transported back to the Middle Ages. There can be various conflicts, like a struggle between a fisherman and a sea monster that has been stealing his catch. And there should be a resolution, whether it's the fisherman defeating the monster or coming to an understanding with it. Also, descriptions of the environment, like the smell of the salty sea air or the cold, damp walls of an old castle, can make the story more vivid.
In a random short story, you can include elements of mystery. For example, a character might find a strange object with no idea what it is or where it came from. There could be a journey, perhaps a young girl traveling across a desert to find a lost city. Also, emotions play a big part. You can have a character who is feeling lonely and then finds friendship in an unexpected place, like a hermit who befriends a talking raven.