A lot of people are afraid to get started because they don’t think they have a good idea. Trust me, an idea doesn’t have to be good in order for you to learn or even make a good film. All you need is a story. It can be as simple as telling the story of someone who rolls out of bed, stumbles to the coffeemaker only to find that she is out of coffee.
The goal with storytelling is to get someone to relate, and with filmmaking, it’s all about the images you use to tell the story. So as you develop your idea, don’t over think it. It just needs to be something you can visualize and execute.
What’s going to make it unique is your point of view. Take the example of no morning coffee. How does she feel when she discovers there is no coffee? How does that translate visually? Does she grab her hair in despair or throw the empty pot against the wall?
Whatever story you want to tell, put it in a script. For the most part, screenwriting is what you see and what you hear. Just remember that it’s always more interesting to tell the story visually. Rather than having the character say, “Oh no, there’s no coffee,” show us the empty coffee container, show us her reaction.
Another thing you will want to do is get feedback on your script. Have someone read it to make sure it makes sense. If it doesn’t make sense, fiddle with it until it does. If it does make sense, still fiddle with it to make it better.