If one tries to think about history, it seems to me - it's like looking at a range of mountains. And the first time you see them, they look one way. But then time changes, the pattern of light shifts. Maybe you've moved slightly, your perspective has changed. The mountains are the same, but they look very different.
Writing a novel - unlike operating a piece of heavy machinery, say, or cooking a chicken - is not a skill that can be taught. There is no standard way of doing it, just as there is no means of telling, while you're doing it, whether you're doing it well or badly. And merely because you've done it well once doesn't mean you can do it well again.
First comes an idea. Then, characters begin to evolve out of the landscape of that idea. And then, finally, characters dominate: plot is simply a function of what these people might do or be. Everything has to flow from their personalities; otherwise it will not be emotionally engaging, or plausible.