I decided to write this post after I received this question on Quora on how to write script for a film or short film. Regardless of what people say, I have always preferred to work with a skeleton of the story.
Before I begin writing, I sit down, take a piece of paper and scribble down the story idea point by point (sequentially). Some of these points might be just one word, while others might be as long as a paragraph. I take an entire day (without breaks) to finish this outline of the story which is called ‘the skeleton’ or structure of the story.
Screenwriters usually make the structure of the screenplay while novelists like myself tend to make the structure of the story. Note the difference, here: The screenplay is how the movie appears on screen while the story can be much more detailed than the screenplay.
Once you finish this skeleton/structure document, you can start thinking how to elaborate the individual points. I prefer writing each scene in a passive voice. This helps in reporting all the actions of the scene along with what could be spoken before we sit for dialogues.
At the end of this step, you will have a document with each scene written out in detail. This will also enable you to identify which scenes need rework . So, while working on the subsequent drafts of the script, you can always opt to work on the 10-page scene document rather than the 150 page script.
Once I am absolutely fine with the scene outline, I proceed to the final step where I start working on the dialogues. Since I have already setup my scenes in detail and also have the idea about what will be spoken by the characters, all I have to do is bring some awesome dialogues among the characters. Of course, this must be done with care as these dialogues can make or break your script.
Your first draft of the script/screenplay is ready. You can start taking opinions or go for readings, or read yourself with a clearer mind. The same steps can be involved subsequently when you will churn out the second or third draft until the final one.