There are as many types of writers as there are...well, writers. But if we take a high-level view, two of the types that fascinate me the most are the Gardeners and the Sculptors. Each end up with a similar final product, but both take very different routes to get there.
The Gardener very carefully plants the seed of his novel in his imagination and allows it to grow naturally, at its own pace, before he ever puts pen to paper. Even then, the story is just a seedling, coming out as only a small part of what the final story will be. Then, he cultivates his newborn form of life, feeding it with subplots and research, pruning dead branches as it grows, until finally he ends up with what he feels is a fully grown and strong plant.
The Sculptor, on the other hand, very quickly builds a massive block of prose, looking more like a hunk of misshapen stone than a story. They are not picky about what they put down, simply cranking out word after raw word until they reach some sort of end. They know most of what this first approach produces will never make it into the final product, but is simply raw material. Then, they take hammer and chisel in hand and smash away everything that doesn't look like a story. Eventually, when the clouds clear, they have honed themselves a novel out of that raw mass of verbiage.
Which are you?