First off, I suppose the old writer's adage "Write about what you know" must hold true - it's certainly helpful. As for originality, I can't say much as I've never taken a course in writing, but I recently saw a comment that makes a lot of sense: A story doesn't have to be new to be good. It just has to be good.
Make sure your characters are strong and memorable and don't worry too much about the world they inhabit. I can only equate it to gaming. If you removed all games which borrow at least some elements of others, there would probably be around half a dozen left. The Last Of Us borrowed heavily from The Road but that didn't stop it winning more awards than you could shake a stick at.