How do I come up with a good specific research question for my graduate school application?

I am a senior in college and I recently decided that I want to become a women's studies professor. Graduate schools want me to put a specific research question in my personal statement.... I did my undergrad in media studies, so I want to research something like this: How representations of women in fictional novels, movies, and/or TV shows inform or alter our understandings of women in real life. But, I feel like I should specify which women or which genre of books/movies/film. I am LF someone to give me a GOOD website that has directions on how to turn a nebulous statement like this into a concise research question that will impress schools. Or if you don't know a website maybe you have some ideas of how I can refine this statement...?