So, on to the third part (For a change, actually done... third). To recap:
Sequel (as in scene/sequel) is the squidgy bit between your action-packed, conflict-driven scenes.
More than just a slack bit of slow-moving nothing, sequel is where the character reacts to their last setback (and it had *better* be a setback, or the story's over) and decides on their next action. And they had *better* decide to do something else to reach their goal, or the story's once again over.
This reaction/decision process happens in four parts: Emotion. Thought. Options. Decision. You can skip a step, but never, never do them out of order. (When that door slams, FIRST Jane feels shock and loss, THEN she acknowledges that Tom's gone. THEN Jane toys with the idea of going sleeping with his best friend/worst enemy, taking up a useful hobby like a foreign language, moving to a villa in Tuscany or joining a nunnery and forgetting men forever. FINALLY, her decision moves the story forward to the next conflict. You don't have to show every step, but imagine how silly it would be to address them out of order...)
Scene (conflict) sets up sequel (reaction/decision) sets up scene, sets up conflict. This cycle continues, pressing your protagonist harder and harder until the story's climax.
And last in the recap, these decisive moments are exactly where the reader emotionally invests in your characters. Skill at handling sequel can make the difference between powerful characters acting in believable ways and books thrown at the wall.
Now, new business!
Sequel is also your greatest tool for controlling pace.
With all their exciting conflict, goals struggled for and denied, scenes move fast. Whether cruel and violent men are plotting the hero's downfall or a smoldering Frenchman just moved in next store, scenes are exciting. They zoom along.
If scenes are the throttle, sequels are the brake. How much or how little you use depends on the pace you want to set, and the difficulty of the plot turns in the racecourse.
Maybe I stretched that metaphor too far. I'll walk it back.
Ever read a book that seemed to fly right through? You whizz from even to event until the last page is turned, close the book and ask yourself, "What was the point?" That's a case of going too light on the sequels.
Or how about a book that seemed to take forever to go not very far at all? You bravely forge through page after page (usually carried by lovely language and not much else), waiting for something to happen. Too much sequel. Waaaayyyyy too much. In real life we may wallow in our reactions and agonize for way too long over our decisions, but try showing that in real time and you lose readers.
Of course, you may win prizes, but that's another story...
How much is too much? How little is too little? To return to my automotive metaphor, picture your story as a mountain road race. You want that pedal to the metal in the straightaways, but you damn well better use the brake on the turns. You might only blip the brake pedal at a bend in the road, or you might have to do a full-on handbrake-assisted bootleg turn to get through a tricky switchback without coming off the road.
One time to get right into the sequel and really grind is on those MAJOR plot turns. I mean the ones that, if the character doesn't choose right, don't just change your story, they end it.
The walls are bleeding. Disembodied voices are telling the family to GET OUT. Why don't they? Short answer: if they do, your story's over in Scene I. Long answer: well, that's where you need to do some real work. Why *don't* they pack right up? I sure would...
From Prince Consort to escaped outlaw in one awful night, we only need short quick checks to stay with Ruenn Maclang's feelings of betrayal and the decision he makes. Later, his decision to seek out his brother gets the time and space it rightly deserves...
The other time you need to dig into your sequel is at the emotional heart of the story. When it's really, REALLY important for us to feel your character's heartbreak, lust, terror, anger, etc., you really need to stop the world for a moment and let that happen. Especially if you're setting up powerful and conflicted choices, and I hope you are.
Dave Robicheaux is such a memorable character precisely *because* of strong sequels. His lifelong struggles with his violent nature are often directly opposed to his loyalty to those he loves. As the blowtorch-sociopaths and shark-souled profiteers smell blood in the water, we're firmly rooted in Dave's conflicts. When his temper gets the better of him, those violent scenes are threaded with a mingled sense of triumph and loss.
Otherwise, he'd be an eighties action movie. Don't believe me? Rent Heaven's Prisoners. Or better yet, don't.
James Lee Burke's sequels also tend to dilate the time in his books. Days, even weeks often pass between scenes, covered in two and three page passages that invest us heavily in the timeless beauty and Arcadian innocence of Dave's world, and the sweet-tinged sorrow of its inevitable loss.
Elmore Leonard uses a shorter timeline. His books often take place over a few days, sometimes even less, and his sequels usually reflect that. Two guys have coffee and shoot the shit, emotional reaction and decision coming out through dialogue. A lonely woman looks around her crappy apartment, and in the time it takes to microwave a Lean Cuisine, decides to steal half a million dollars. Quick pace, but full investment, it's an artful balance.
I shouldn't have mentioned Leonard. A wide variety of subtle tools do a huge amount of work in every passage. One could devote an entire blog just to pulling the tools apart and looking at them. And he's that sort of master makes it look effortless.
One last thought: This scene/sequel construction is just one way to look at your stories. This isn't Newton mechanics, this-way-and-no-other type stuff. It's more a quantum physics particle-wave-and-four-kinds-of-spin-its-state-depends-on-how-you-look-at-it sort of thing.
As always, take what you like and leave the rest... :-)