Earlier this week I completed the first end-to-end outline of The Palace of the Red Desert — not a complete outline, but the first one that covers all the plot territory from A to Z. The next move is to step through the document and flesh it out — go over it obsessively, see how things I wrote earlier need to be revised in the light of things I wrote later, add details I missed previously, make notes to myself about what to emphasize, and so on.
This isn't really an "outline-first" approach, because I already have a rough draft of the first couple of chapters sitting around. It's more like a "bootstrap-then-outline" approach. FIrst, write the first couple of chapters off the top of one's head, just to find the right tone and direction for the material. Then stop, assess, plan the rest, then begin the story in earnest.
Shifting to this method wasn't something I planned consciously, but the payoffs were hard to ignore. My old strategy was just to form an image of the whole book on my head, dash through it from start to finish, and then fix it up in successive drafts. That turned out to be a time-sink, and an effort-sink as well: too much time spent on bringing the story to the place it needed to be, instead of starting from that point and deepening it.
One mistake I didn't make, though, even with that old way of doing things, was not knowing where I was going. Every book I've finished has had the same basic idea: a specific idea at the beginning, and a specific mood or flavor to the ending. In other words, I don't know what the details of that ending are, but I know what kind of emotional effect I want it to have on the reader. (I've touched on this before, but it always bears repeating/elaboration.)
That emotional effect is asd good a destination as any plot — better, even, since plots are interchangeable and moods/emotions are not. Plot + mood/emotion = expression, and having a different expression for each story you tell is a great differentiator. (I'll go into this more another time.)
I'm tentatively slating a formal start for the first draft sometime at the end of July or beginning of August. If I'm diligent, a full first draft could be ready by the beginning of next year.