We’ve all heard some version of the rocks-in-a-jar life metaphor, right? The basic premise is that we only have a finite amount of time on this earth (the jar), so we need to make room for the things that really matter (the big rocks) and not let the smaller, less important things (pebbles, sand) crowd them out.
I’ve been working with both fiction and nonfiction authors lately on a strategy that borrows from this metaphor: decide on your key plot points first, shape them into an arc, then fill in the story with details—not the other way around. Too much filler makes for a rambling, pointless story. If I'm five chapters into a memoir or novel and my head is spinning trying to remember names and places, but I'm still not sure what the main character wants or is trying to overcome, I'm not going to care how that book ends and will likely pull the plug on finishing it.
When planning out your novel or memoir, besides deciding on your central premise or theme, coming up with a list of key plot points should be your first step.
Once you have those in place, it’s easier to decide which scenes to include, and from there, which details, pieces of dialogue, and other narrative content to add around the big rocks.
Filling a jar with rocks is one thing, you might point out, but how do I know which of the events and incidents in my character's life are important enough to include in my story arc? In other words, how do I know a big rock from a pebble? Here's a clue: a key plot point will almost always involve a crisis of some kind for the main character (or, in a memoir, you), a moment when they have to face a fear, an internal flaw, or an external foe, and are changed in some way because of it.
Think of the big rocks as the big “a-ha” transformational growth points for your character.
Without those growth points that inevitably lead to a culminating clash of conflicts, there is no story. There’s only a series of scenes and descriptions—which may be related or grouped in some way that makes sense to you, such as chronological, but which doesn't make for a compelling, page-turner of a story. And let's face it, no one wants to read “filler.”