There's a motto that can give you the key to coming up with a stronger plot for your screenplay. John Lennon put it into his song, "Beautiful Boy," but the first person to have said it seems to have been a cartoonist named Allen Saunders, back in 1957. The saying is:
Life is what happens to you while you're making other plans.
Often the problem with a plot is that the protagonist doesn't have any other plans. He or she is there, apparently waiting for the story to start, and then it does. It continues, and it concludes. Lots of things happen but we feel somehow it isn’t satisfying. It's like eating cotton candy for dinner.
The motto in action
I'll give you an example. Here is a very brief description of a plot:
A woman tries to find the son she gave up when he was an infant, 35 years ago.
OK, interesting situation, plenty of scope for drama and even some comedy.
Now try this one:
A woman trying to find the son she gave up when he was an infant, 35 years ago, is diagnosed with inoperable cancer and given only one month to live.
Of course it's much darker, but I think it's also a lot more interesting. Now there is a ticking clock. She has to find him very soon or it will be too late. There's also a dilemma--assuming that he would be happy to reunite with her, would it be fair to do that knowing that she will once again abandon him so soon?
The thing that doesn't fit in with our plans doesn't have to be terrible. A light romantic comedy version might be:
A woman trying to find the son she gave up when he was an infant, 35 years ago, falls in love with a man who is only a few years older than her son.
Now her concern is how the new lover and the son would react to each other. Does she want to bring a complicated emotional situation into her life just as she's finally found love again? Would having her son around constantly remind her new lover of their age gap? Maybe she's lied about her age in her dating profile and her new beau thinks she's 45, not 55.
In some cases you may feel these kinds of complications would overshadow your core story or turn it into a melodrama. There's definitely danger of that in the cancer version of the story. That element is so big that it could detract if you want to explore the more subtle feelings that come with her search for the son she gave up.
Option One: Flip it. In the version above, her plan is finding her son and the unexpected life event is the terminal cancer. You could flip it around so that when the story opens, she is planning to continue to lead her normal quiet life for the little time she has left. Then something happens--either she learns the son is trying to find her, or in the process of getting her papers in order she comes across a picture of the boy just after he was born and that triggers her need to see him before she dies.
Option two: Think smaller. In this case, forget about the cancer as a story element. Instead, maybe the woman's closest friend passionately believes she's being foolish to dig up the past and it begins to disrupt her relationship with the person she assumed would be her best friend for life and who is her main source of emotional support.
Or maybe the search interferes with her work and she's in danger of losing the job she loves and planned to keep doing until she retired.
Or perhaps in the process of looking for her son she meets another person from her past who she'd planned never to see again.
Match the nature and scope of the unplanned event to the genre and style of the story you want to tell.
How to use this method
A good way to use this method is to start with the core story you want to tell and then brainstorm the answers to these questions:
* What development would make it much harder for the protagonist to reach the goal?
* What development would test the protagonist? That could be on the physical level, the emotional level, the moral level, the spiritual level.
* If the core story is very dark, what unexpected development might give you some opportunities for comic relief? If it's a comedy, what might help you expose the deeper side of your protagonist?
* Which of your ideas best fits the core story the way you want to tell it--complicating it but not overwhelming it? Do you need to make it bigger or smaller?
The coincidence rule
Some writers worry that this leads to events that seem too coincidental, but I think the old rule works: you can use coincidence to get your characters into trouble but not to get them out of trouble. All of my examples are about getting the characters into trouble.
Look for this as you watch or read
Try watching a few movies or TV episodes or reading a few novels with this in mind.
Do the more involving ones use this kind of structure?
Do the ones that feel less real or satisfying ignore it?
Of course the most important question is how you can use it to make your plot stronger. If you're just starting on a script, build this in from the very beginning. If you've written a first draft that's missing this element, it could be the key to a second draft that gains power and really works.