I'm still at least 20,000 words from the end of my first draft, but I think I've figured out what works for me. Note everything I say here is in reference to me. It may or may not apply to you.
This is my third try at a novel. Each time I've tried a different approach. (Incidentally, each of the three has been a different genre, but I don't think that has much bearing on what I'm saying here.)
The first time, I just started writing one evening, with no real plan, and then proceeded to polish that first chapter to within an inch of its life before I went on to another chapter, and so on. I got to a certain point and some of my readers pointed out many flaws with the plot, and after deciding I couldn't fix them, I ditched several chapters and characters and started over from a spot in chapter two. I ditched large amounts of writing in search of a coherent plot, and kept trying to make the plot more and more complex so it would be "good." Eventually, I had the beginning, a bit of the middle, and an ending of sorts; I'd gotten frustrated and written the high points of the story.
My lesson learned: If someone tells me to start over, even more than one someone, say no. Unless I truly hate what I'm working on, which has never been the case. Starting over leads to unneccesary complication and thus to confusion and eventual frustration. Perfection is elusive and won't appear from banging my head against a wall.
Second try, I thought I'd go for a straightforward fantasy quest-style plot; that would be easier than sf taking place in two separate environments. I made up a very basic outline and some characters, and did a lot of research to use as the basis for my fantasy cultures, a new and exciting thing for me. I wrote an opening chapter. I wrote some other chapters. Some of my readers told me what was wrong and that I needed to start over from a different place in the story. All very true, but see above. I rewrote the opening couple of chapters at least three times, I can't even remember now, and began to get bored. Then I decided to avoid all my confusion of the first try and made a detailed outline, breaking each chapter into five scenes that would be about a thousand words each, with a total of about fifteen chapters. I started writing to the outline. About chapter seven, I didn't like the way things were heading. I didn't need some of the stuff in the outline; it wasn't working as I had thought it might. But if I didn't stick to the outline, well, I wouldn't have stuck to the outline. I ground ahead with the outline, bored and angry and dissatisfied. Then I stopped writing altogether.
My lesson learned: Once again, do not listen if someone tells me to start over. Do not outline in anal-retentive detail, because I don't have the skill/practice to do so and take everything into account. I don't know everything at the beginning, like some writers do. I cannot follow an outline rigidly, because I will become bored and feel I have no room for inspiration, and I will shove aside great ideas because they don't fit in a pre-determined frame, feeling the whole time like I've killed something.
My third try is now, though it has a lot of history (not just because it's a historical!). I had collected a lot of information about WWI and 1919 some years ago, before I started the fantasy novel, and had some characters, but they were in search of a plot and also I thought a historical would be too difficult to write. I put the notebook aside. A few years later, I got a new workshop.
Then I started thinking about the characters again, and wrote a scene for two of them. Then I tried to write a short story using the few ideas I had. I workshopped the short story and got excellent comments. I applied them and the story still didn't coalesce. My sister suggested it needed to be a romance, an idea I'd considered in the beginning but then put aside because I write sf/f, damn it. Apparently, I also write romance, too. Sort of. (Back then, I hadn't read much Romance, but now I have, and have gained a clear idea of the genre.)
My method this time is based on something I learned at the very first meeting of my new (and current) workshop, which is [drumroll] Give yourself permission to write shit. This is not as easy as it sounds, but if accomplished, can be very freeing. Like I imagine Zen archery feels. It involves writing the whole draft before even allowing myself to consider going back and changing anything. So, I'm doing that. And I think it's my method.
In more detail: I didn't outline, beyond knowing in my head where the characters came from and where I wanted them to end up. I wrote many chapters of draft with practically no plot in them while I figured things out about the characters and what plotlike things I could do with them in future. I allowed myself to have fun, and when I wasn't having fun, I looked forward to the next fun bit as a reward. I remind myself not to be scared (it doesn't always work, but I try). When I felt like I needed structure, I made a vague mental outline of four chapters or so at a time. I kept writing, no matter what. Now I have 53,000 words.
My lesson learned: this is the method for me! It's fun! I feel smart! I laugh in the face of outlines! I figure things out as I go along! It's the perfect method for my somewhat convoluted thinking patterns. At least for this novel, it is. [sigh] What will happen when I try and do a rewrite is another thing entirely...I've never gotten that far before! Stay tuned.