Now is a really good time to start reading scripts. If this isn’t a practice for you, I recommend it. Watching a ton of movies is fun and can help when visualising your own movie in your mind’s eye, but the best way to understand the pacing and the anatomy of a script is to read one. Drew’s Script-o-Rama is a good place to start looking for free readable screenplays. You can also purchase your favorite screenplays at the cine file.
By now you have a rough idea of what you’re going for, so as you develop your story it doesn’t hurt to have some examples of successful scripts to compare to. You’ll also get a feel of how a screenplay reads and consequently how you should write. Screenplays are separated from other written works by more than just format. They have their own way of illustrating events for the reader. For starters, unlike most novels, screenplays are written in the present tense. You are describing everything that takes place as though it is happening right now. For some, it comes naturally and it may become difficult to write in past tense. In some of my short stories, I have had difficulty with slipping in and out of tenses like a bad actor who can’t carry an accent.
Another, more serious obstacle to overcome is learning how to describe only what will be visible to the eye. In books, you can write the thoughts and emotions of a character and draw from the abstract. You probably don’t realize how often you describe what cannot be seen. This means if something is important, it can not merely be included in the action part of the script, it must be spoken as a line, or shown visibly to the audience. Learning how to write this way just comes from practice and learning how to recognize when you are telling something that cannot be shown. Even if you plan on directing your own movie, it is work that must be accomplished. If you write it poorly, you will need to come up with an alternative later on.
A terrific excercise is to write a deleted scene. Use your main character but don’t make the scene be part of your movie. It’s just a situation. The scene will have no dialogue. Just give it a slugline (INT. OFFICE–DAY) and beneath it will be a full-page of action. Make a mini story, with a beginning middle and end, involving your character and no dialogue. Read it carefully and ask yourself if there is anything you would have trouble filming. if you want a fresh look, ask a friend, whom you don’t mind reading your stuff. Keep tweaking it until you have a knack for the language. This excercise and getting a good feel for how other scripts are written will help to get you in the mindset you need to get to work on writing your screenplay.
In the mean time, you have a very general synopsis of your story with a well planned beginning and end, and maybe a jumbled up middle with some key plot points. You probably already have a couple of paragraphs worth written out, so start another page and fill this one with a thorough summary of your script. Start with your first and third act summaries and flesh them out a little until they make up half a page. Fill in the middle with whatever you’ve got for the second act and then some. This is the really creative part. Let your mind wander into possibilities. create complications and find resolutions and always build toward your end result while keeping things fresh and interesting. One quick and easy method to plotting your second act is to make your character want something other than the goal. You can take him away from what he wants all while leading him where he needs to be. The opposite works too. Giving your character exactly what they want, leading them away from the goal. If you go that route the turning point will have to swing your protagonist in the direction of the third act. If you go the other route, you’re going to have to weigh out the characters intentions against the plot and resolve that conflict before he has to face the big bad at the end.
Think about the main through-line of the story, but also consider the relationships of your other characters. what do they want? How are they involved? What possible side stories or sub-plots could better illustrate the theme. My side stories come from the need to demonstrate a different side to a character than is needed for the main plot, but comes into play heavily as all things come to a head. I also have a (gasp) romantic subplot. Often complained about and misunderstood, even (especially?) by writers is the romantic subplot. Many people believe this part of a movie is thrown in at the last-minute by a producer or someone who wants to expand the audience. More likely, it’s written in, by the writer as a ploy for emotional investment, or to fill in gaps, or both. People can see through a bad subplot, so make yours count. While you are fleshing out the story, pay attention to pacing and balance. Each sentence will probably describe a scene, or two, so try to imagine the story transitioning from line to line and see if your main character is over burdened and needs a break. Order doesn’t matter at this point as much as just getting all of your main plot points written down.