Before I start, I want to make it clear that I am by no means done talking about the planning stage, by the way. Just because I leapfrogged from the incubation stage of writing into a full-on common pitfall of novelists doesn't mean I won't come back. And that is in of itself a lesson, of a kind: one doesn't simply progress in a perfectly chronological line of ideas, planning, plotting, writing, editing and publishing, in the same way that a band doesn't put an album together in the track order that you see on the end product. There is much flitting back and forth, reviewing old ideas and writing that need tweaking because you made awesome changes later in the book and you need to add some appropriate foreshadowing or have a certain character make an ominous early appearance.
And in a way, the progression of your story is similarly unfettered by time. For those of you who have read 'Tick', you'll know that there are splashes here and there of flashbacks, delving into key moments of Tom's past.
But the story didn't start there, did it? It starts on that fateful night, right when Tom spots his name printed where a train station should be.
But wait a minute, there is story to be had before that, right? The flashbacks are plenty eventful, and certainly key to the plot. So why didn't I kick off at the very beginning, when Tom was but a wee lad off on work experience?
Ah, well that's not where our story starts, is it? What we are talking about here is the difference between the 'stasis' and the 'trigger': the stasis is the normal life for our protagonist, where things are as they should be. Think Woody in Toy Story, enjoying his time with Andy before the birthday party, or Harry Potter living under the cupboard with the Dursleys.
This part is not the prime interest to our readers, but merely scene setting. Our story really kicks off with the 'trigger': that moment in the story that is beyond the control of the protagonist that kicks off a chain reaction of events, disrupting our protagonist's stasis. Sometimes, that trigger can hint at better things to come (the arrival of Cinderella's fairy Godmother or the mysterious envelope arriving for Harry Potter), leading the protagonist deeper into the plot. Or the trigger can be negative, pushing the protagonist out of his or her comfort zone (the arrival of Buzz in ‘Toy Story’, or the landing of Vincent's first victim onto Max's taxi in ‘Collateral’).
The trigger is the lead-in to the main bulk of the story, and is our first and most important indicator of what our protagonist is up against. Now, if it's a pleasant trigger (like finding a treasure map), this usually leads on a quest to attain more of that pleasing breaking of the stasis...for better or for worse. Or if it's an unpleasant trigger, the protagonist sets off to restore to the stasis of before (Woody seeks to oust Buzz, Frodo heads out of the comfort of Bag End and the Shire).
Already, you may have figured out this whole stasis-trigger dynamic isn't as cut-and-dry as "normality, thing happens, story ensues". Let's look at ‘Jumanji’ as an example. There could be feasible arguments made for two possible triggers: when Alan and Sarah first roll the dice, or when Judy and Peter first roll the dice. You could argue that this is ultimately Alan Parrish's story, therefore his first play of Jumanji is the trigger of the overarching story. On the other hand, there is such a prolonged period of time between their play and when Judy and Peter first play Jumanji that you could argue that a new stasis has been set, and this is the trigger that really sets our heroes off on that quest. But on the other other hand, the town was clearly in better shape before Peter disappeared, and the eventual return to that time and world indicates that the dystopian-esque town was a disruption of the original stasis...
And so on. not quite so straightforward, huh? But that’s fine! ‘Jumanji’ as a story works, and works very well because it twists the rules to the needs of the story it wants to tell, and does so effectively and economically. Even if you identify a clear stasis and trigger, it doesn't necessarily point to the story's structure. Some stories have a prolonged stasis before the trigger (it’s a few chapters in before Harry gets his first letter from Hogwarts), others start right on the trigger (Kafka’s ‘Metamorphosis’ begins with Gregor Samsa awaking to find himself transformed into a “monstrous vermin” – which incidentally provided inspiration for one of the key moments of ‘Tick’). Some stories begin with the trigger already having happened, with the quest of the protagonist hinting at some event in the past that brought about the events of now (in ‘Kill Bill’, the bride is already on her revenge spree and the true reason is revealed later on in hints and flashbacks).
And your trigger doesn’t need to be a huge and clearly signposted snapping point either. It could be prolonged (Harry Potter is dragged halfway across the country before the contents of the letter are finally revealed to him), and it could be a huge event (a zombie apocalypse) or something so tiny it is seen as insignificant until it is looked back on in retrospect (in ‘the Amulet of Samarkand’ by Jonathan Stroud, Nathaniel steals a rare trinket from a magician who wronged him by way of revenge, but as the story progresses it is revealed that the trinket is far more powerful and dangerous than he thought). In all of these cases, the choices made are all justifiable in terms of the author’s wish to intrigue, shock or disorientate their reader, how much time they feel they need to set up the world before they begin the story in earnest, and their own style as well.
Regardless, whatever happens, the stasis is your ‘straight line’ and your trigger is your first ‘blip’. So it’s all about identifying the story you are wanting to tell and finding where your protagonist’s trigger is, and how much set up (if any) is needed before the trigger is hit.
Because, of course, there may be a larger over-arching story at play in the background (think of the war against man and machine in ‘The Matrix’), but while this informs our story and gives the plot a body and context, this isn’t the story. Again, we come back the first point of identifying what is the story, and what is setting the scene. It can be tricky to identify which is which, but in all but the most exceptional of cases we need that character (or characters) to identify with, who will be our eyes and ears in this world. Their personal trigger may be smaller than the events around them (the death of Luke’s family on the farm in ‘Star Wars’), but it resounds with us so much more because it is personal, and it opens the gate for the protagonist (and us) into the bigger picture.