My wife has grown very familiar with my habit of checking my watch during all the major plot-points of movies. I'm sure it gives the impression that I'm bored, but she knows what I'm actually doing is noting where we are right now in the three-act structure. I'm like, "Wait the couple is finally having sex? Yep, here we are at the midpoint."
Hollywood films are notable for always hitting the right beats at the right times, to the point that it's almost more noteworthy when a film _doesn't_ do this than when it does. However, most Hollywood films aren't what I'd call "well-constructed." They're like stories told by drunk people. They have the outer form of a coherent narrative, but the actual events don't add up.
For me, a well-contructed story needs to do more than have tension that rises and falls at the right moments. It requires a broader coherence between plot, premise, character, tone, and theme. Essentially, the events in the story should be the right ones to bring out the conflict that's inherent in the premise. The most illustrative examples in this vein tend to be noir thrillers. One of the best-constructed books I can recall reading is Scott Smith's A Simple Plan (which was filmed more or less faithfully by Sam Raimi). In the novel, three friends find a bag containing four million dollars, and in order to make sure that nobody comes looking for it (they have an inkling that the bag is from a bank robbery) they decide to wait at least six months before spending it.
Well of course this falls apart almost immediately. But the book is relentless in the way it simply allows its characters to grind away at each other. And every element, from the small-town Ohio setting to the mobsters who eventually make an appearance, is designed only to increase the tension and to serve the book's central theme: "What would you do in order to escape from a dead-end life?"
Obviously this theme is an age-old one, and I don't know that A Simple Plan is particularly thought-provoking in its treatment of it. The breakout character of the novel is actually the protagonist's wife, who initially seems like a voice of reason and then gets more and more wrapped up in the plot. Otherwise everyone behaves more or less as they need to.
I wonder now if the book's strength isn't actually its weakness. Its tight construction means that there aren't very many opportunities for the protagonists to slip their leash and truly act against type.
I'm revising my own second YA novel now, and in every phase of revision I've tightened the construction. Where once it was shaggy and meandering (and ran to over 90,000 words), it's now narrow, tightly-focused and clocks in at just over 60,000. The plot proceeds with what is, to me, relentless focus, and every element is carefully aligned to increase the pressure.
And yet I wonder how different the book truly is from the previous, much shaggier versions. There's an aesthetic joy in a well-turned plot, but I don't know that it's the kind of thing that makes a book truly timeless or great. Yet for some reason I've found myself obsessed with aligning all the story elements--to the point where I literally rewrote the entire book just four months ago, and now in this second revision pass, have rewritten at least 25% of it.
So much of writing a book is a matter of structure. It's my feeling that if you can write something that feels novel-like, then you've come most of the way towards writing a salable book, even if your plots, characters, and premises are shop-worn and your writing is merely serviceable. The mechanics of pulling people through a book really are sort of a simple thing, but they're so essential to the novel.
What's hard, I think, is integrating that sense of mechanics with the story that you want to tell. Because at least for me the story doesn't automatically come out fully-formed. And every attempt to turn the story into a better-formed object has the potential to lead you down a false path, because when trying to craft a plot, it's very easy to reach into the old familiar bag of tricks. You find this oftentimes when getting comments from veteran editors or grizzled old writers. They almost have an intuition for twisting your story into something that can sell. But the result is oftentimes not the story you want to tell.
And yet some stories cannot be told. Protagonists, in my experience, need to have at least a hint of the heroic. Most attempts to tell a story about 'ordinary people' (where ordinary is synonym for weakness, self-pity, cowardice, and selfishness) are doomed to failure, simply because those are precisely the qualities that are unworkable within a traditional story structure. In order to even enter into your story (to fight to keep the bag of money, for instance, instead of chickening out at the first sign of trouble and reporting it to the police) your protagonist needs a hint of the larger-than-life.
Which leaves authors in a troubling position. The more unrealistic your characters, the easier it is to tell a story with them. And if your aesthetic aim is to present characters who are real, or at least more human than normal, then your job becomes correspondingly harder. And perhaps that's where my obsession with well-crafted stories comes from. Because the truth is that structure is the glue that holds together the story, and if you want to make something truly striking and unique, then you need a glue that's much stronger then if your story is merely following convention.