You could try ultilising your recently discovered understanding of Gothic markers and tropes by writing a Gothic short story. Obviously, I would want it to correspond to the kind of genre markers that you have been learning about.
The best thing you can do is read Gothic stories. Here are a few bits and pieces online to guide and help you:
Frankenstein – Mary Shelley The full novel. You could read it all if you wish!
Dracula – Bram Stoker Again, the full novel.
Classic Gothic Ghost Stories Some great stories here, including Washington Irving’s Sleepy Hollow.
Gothic Tropes A list of ideas and themes explored in pieces of Gothic literature. It could help.
Before you embark – do think about when your story will be set. Does it have to be in the past? Now? The future?
As always, when writing a story, consider carefully how you are going to evoke mood and atmosphere through the setting, the characters and their actions.
Best of luck!