Think about the story of Macbeth. Who or what struck you as odd about the characters or the events? Is there a part of the story that you can bend into your own narrative? The odd event or character should appear in your narrative.
Basically write a story that in some specific way relates to the plot, characters, events, themes... of Macbeth.
1. Be sure the story has details in character and description.
2. Be sure to plan your story out. Make things happen, but don't just say "Mac entered the office building." "Mac spilled out of the Uber without looking back, scrambled up the cold granite stairs, and vanished through the revolving door."