...a thousand words, would you write a thousand words (or, say, 100K words) the same way you'd paint a picture?
For me, it turns out I would.
I'm no skilled artist, but I have painted a few things--in watercolor, acrylics, even oils--and I tend to approach that art form in much the same way that I prefer to approach the writing of a novel: I first do a quick pencil sketch on the canvas (like a plot outline or, my fave, Blake Snyder's 15-point beat sheet). Then, in broad but fairly careful strokes, I paint the sky/background and block out the big areas where the important visual stuff is happening, slowing down in places where I want to make sure I'm shaping it correctly (like writing that first, messy draft that takes me eons but is usually structurally solid). Then I focus on the main image, fleshing it out so the right parts stand out in the foreground and the right parts blend in as seamlessly as possible with the background (the second, third, fourth drafts where my focus is on the action/reaction in the individual scenes and on strengthening the emotional logic and flow of the narrative). Finally, those significant but small details are added in last with my tiniest brush tip (the story particulars that make the characters or the setting pop and the novel's important themes emerge, plus all the wordsmithing and punctuation checking, etc.).
Other people, of course, paint (and write) differently but, for me, this way has proven to work best and, since I'm currently writing my 10th novel, I've already done my share of experimenting; I'm happy with this process.
Only...this is not how proposals are written. Not at all. Some well-established (or very lucky!) writers can simply present a story idea in a paragraph or two and sell a book based on that. For those of us who need to submit a synopsis + 3 chapters, though, well...I don't get to write like I paint.
For proposals, that first step is fine for me. I still get to start out by working on my overall plot (not only because I need it to write but, also, because that eventually becomes my synopsis). But the next step--the time-consuming broad-stroke first draft--is shot to hell. I only have time to write 3 or 4 chapters in the new manuscript draft, then I have to STOP EVERYTHING and irrationally--from my POV, of course--go on to the next stage of revising (and revising again) whatever is in those early chapters before adding in "final" details on a manuscript that is not, in my case, remotely final. To me, that would be like working on a painting where the pencil outline is sketched but only the bottom-left quadrant of the canvas actually has paint on it. In that quadrant, however, almost everything has been done and, later, assuming the project is commissioned, the artist would need to go back to it, freshly mix all of the colors again and try to get the shades, lines and contours of the remaining three-quarters to match that one completed quarter.
To the painter (and the novelist) in me, that's a little crazy-making...however, until we've earned the reputation and the opportunity to call our own shots, we adjust our process to fit the industry, right? Right. So, you'll all understand what I mean when I say that I just sent in a partial painting, um, new-book proposal to my agent this week, and I'm hoping I'll have the chance to pull out my watercolors again and finish this project...