It took me a long time to realize that heroes need special skills. You can’t just start out with a blank-slate everyman who encounters a problem and solves it by reacting in the way that anyone would.
Instead, the hero must rely on a specific set of special skills that pre-date the movie. Harrison Ford in The Fugitive was a doctor, so he finds ways to use his medical skills to clear his name. Will Smith in Enemy of the State is a lawyer, so he uses those skills to get the NSA off his back. Neither one of them suddenly busts out with kung fu moves...
In those cases, the heroes made use of their day jobs, but often you’ll find that those aren’t enough to get the hero out of every scrape, and the hero suddenly need a heretofore unmentioned skill in order to overcome a specific obstacle. Each time this happens, you can stop, go back, and pre-plant a reason those skills exist, or you can do what I do: just keep going, and fix it later.
You wrote your screenplay by going forwards, but now’s your chance to re-write it backwards. Set up a plant for every pay-off, so that, as the audience gets to gets to each twist, they’ll say “Ah ha!” instead of “Yeah, right!”
The trick with pre-establishing special skills is to do it subtly and organically. Here are contrasting examples:
- In Aliens, Cameron establishes early on that Ripley can run the fork-lift exoskeleton, which will come in handy later. He hides the significance of this by turning the plant of it into a nice little stand-up-and-cheer moment, wherein Ripley proves that her lowly dock-loading job can be useful in her new military setting. By giving the moment a meaning of its own, he hides the fact that he’s really just setting up a special skill that Ripley will need later.
- In Salt, on the other hand, Salt’s husband is an expert on spider-venom, which seems random and apropos of nothing. Only later, when Salt uses a ridiculous spider-venom bullet do we realize why they put that in there.*
This is why, as per the breakdown I got from Simon Kinberg, producers are so focused on the amount of plant-and-pay-off in your script: it shows that you literally know your stuff backwards and forwards, that you’ve been circumspect, tightened all the screws and battoned down the hatches. This assures them that the script won’t fall apart under pressure.
*Referring back to the debate in the comments of this post, this is another reason why I allow myself to make minor decisions, such as the hero’s previous jobs or the spouse’s expertise, somewhat randomly as I write the story, instead of trying to make every detail thematically significant in the first draft. I often have to change those details later in order to shore up developments in the plot, and I would be reluctant to do so if I had already made them thematically significant.