There's a temptation for beginning novelists to use the "slow build." They figure since the novel is a long form, they have ample leisure to establish setting, get their characters in place, and so forth, before getting around to anything actually happening. This wearies the reader almost at once. Why should I read a book where I have to wait a hundred pages for an event, when other books start rolling on page 1? Another novelist will have a wild, super-intense opening scene, and then let the story settle into a long morass before revving it up again with any action. This hypes the reader's interest, but makes him impatient and rightly irritated. Often, readers who even bother to get that far discover that the best part was the first few anyway. The opening scene is a promise, and if you break that promise, the readers will come at you with sticks.
I suspect slow-build novelists haven't spent enough time thinking beforehand where the story is going, otherwise there'd be a lot less prologue and we'd get there already. There's nothing wrong with thinking through a story in writing first, meandering around until you find what you were seeking, but that doesn't mean the reader has to do it with you. This is why God gave us the delete key. Likewise, I think the common cause of having an explosive hype scene and then nothing is that the hype scene is all the writer had in the first place. He should have mulled more carefully on the consequences of his opening scene before proceeding.
I'm re-reading The Plague, which I know is about so much more than the plague of the title, but I want to consider it today purely from the point of craftsmanship of plot. Camus devotes two pages - tops - to describing the ugliness and banality of Oran. Even here, he is creating suspense, a sort of "we-never-thought-it-could-happen-here" sort of mood. Then, the rats start dying.
The death of the rats is grisly and spectacular, wierd and compelling. They all come into public as they die, and there prove to be more of them in this ugly coastal town than anyone could have imagined. There are rats everywhere, in streets, trashcans, hallways - still warm bodies underfoot. Just as the rat deaths taper off, a concierge develops fever and swellings and dies in horrible agony.
Then the human deaths begin.
In a very few pages Camus siezes our attention - the ugliness of the town is a promise, and he fulfills it with the death of the rats, and the rats are likewise a promise, and he follows on their heels with human deaths. We never loiter around with the characters backstage waiting for events to start; instead the characters are in the middle of the events with us - a doctor, a priest, a writer, a criminal - doing what they would do as first rats, then people, begin to fall.
That's how you do it.