Take control of your career
In recent BBC survey Lord of the Rings was voted the greatest novel of all time. As it happens, almost all of the top ten had been adapted for film. You could, from this information, work out that most cinema goers don't actually read that much and most film makers do. I whole heartedly support the others, when they say that reading, books, magazines, watching documentaries and reading newspapers is a really good practice for any good writer.
The other thing I usually suggest to writers, is that they become people watchers. When you are out and about, listen to how people actually talk to to each other, look at how people behave, when they are alone, when they are with other people.
The stories we tell are all about being human, the more you understand people, the better a writer you will be.
The other thing to remember is that like any other skill, it takes practice and the more you do it, the better you become. I cringe at some of the stuff I wrote in my teens, but writing it led me to where I am now.
I would also suggest that you don't wait to be discovered as a writer, but take control of your career and make films as well. You'll learn more about what works and what doesn't by trying to produce your own scripts.
Don't get down hearted if your early efforts aren't world shaking, just accept that they are all part of the learning process.
The main thing though is to enjoy it.