Many pupils can lose interest when creative writing is mentioned, because they associate it with lengthy pieces of extended writing. One and two line stories can be really helpful for engaging with the key components of good story, without the stress of having to write much.
Below is a short story that could provide useful starting points for modelled or shared writing. It is useful for identifying key information that creates interest, without being too long.
One day I went to the moon. It was nice. I ate lunch and came home.
Ask your pupils, in pairs or small groups, decide what detail this story needs to make it interesting and appealing.
Ask them to note the different ideas in their groups. Are there any features that everyone agrees on?
Then ask them, as a group, to extend this story to make it more interesting to readers their age.
Then ask them to swap extended stories with another group.