There is a beauty in the freedom a prose author has. You can literally write about anything. What is fascinating, though, is working on a low-budget film. Can you write a story/script for a ten-minute or less movie?
If you're a creative type, you may be able to come up with a story for a short film, but then I ask, can you make it a reality? Can you find or make the location? Can you get all the people you need? Can you get all the effects done that you want?
The logistics of making a movie are significant. You may end up throwing out countless ideas because they just aren't feasible to execute. But these difficult can also be aids.
Start with your resources. What locations do you have access to? What kinds of special effects can you create? What props do you already have?
Writing students often get prompts that are similar. Something like, write a story that involves a pilgrim, a volleyball, and a meteor. Although that example may seem ridiculous, you never know what kind of situation you may end up in.
I'm currently working on a short film about a man who works in a power plant on a 12-hour night shift all by himself. During that time, he experiments on people to try to create a zombie disease.
Sounds pretty damn crazy, right? It is. I would never have thought about that as a story idea were it not for the fact that we had access to an actual power plant that happens to have a laboratory in it. Once we had the location, the creativity came from that. It is a story which is both compelling, but approachable. And most importantly, it is one that can be made.
I don't think that everybody should necessarily try to shoot a movie, but at least think about it logistically. If you were going to make one, what could you do? And knowing those limitations, what kind of story could you make?