Nicolas Cole says writers waste time by skipping outlining and jumping straight to drafting. Before you write, pick a working title and sketch out chapter titles to test whether your book actually delivers on what you promised.
Chapters
Where I think writers waste a lot of time is they don't clarify the title enough, and then they skip the outlining phase, and they go straight into the writing. And then what happens is the writing fails to deliver on the promise of the title, 'cause they're still trying to figure out what they're trying to say. And so what I would do, I think the best way to stress test a title is to come up with a working title, even if you're undecided on it, and then go through the first part of the outlining where you actually create the chapter outline. You don't have to flush the whole thing out. You don't have to go through and expand it yet. All you wanna see is you wanna see the main title and subtitle, and the high-level chapter outline. And even just that step will reveal to you, is this the book that I want to write? Is this a promise that I can deliver on?