Have you ever heard this rule for organizing a presentation? “Say What You Are Going to Say, Say It, Say What You Said.” Try to translate that into writing and you might end up putting your readers to sleep. So many formulas to create coherence breed boredom instead. Organization in writing requires a progression. What you put down on paper must be thought out first to show some type of logic and coherence that has a goal, without being completely predictable.
There are multiple organizational diagram: branching, bridging, bubbling. But think about it; how exactly would you put together a composition to read like one central idea, with all the related sub-ideas jutting out in different directions? Writing is linear so basically you only have two “big picture” organizational schemes available: sequential and non-sequential.
Fiction, biography, history, and the unbelievable true story are predominantly sequential. But flashbacks, flash forwards, clusters of events and parallel accounts all break into the march of time so it doesn’t always move forward. There is a larger, overshadowing orderliness based on the theme. Being conscious of this will help you know when to insert the time bending devices, such as flashback, because it fits. Non-sequential writing may move from topic to topic based on location, importance, people or some other criteria such as a biological tree. It will also include the occasional chronological sections. In the end both sequential and non-sequential writing are blends.
Then, there is the digression, the comment only barely touching the relevance that expresses your pet peeve, or some tangent idea. So when is it okay to digress? There is no hard and fast rule (which is true for most other topics in writing, too). You must decide if the digression adds to the color of the story, gives insights to your view of the world or simply makes the piece incoherent. As with other characteristics of voice, organization requires judgment, and that is why it reflects some your uniqueness.