A master's student wrote today, asking me how I used my writer's notebooks; this is most what I replied:
I don't keep a daily notebook like some authors do with observations and so forth.
Basically, I just grab one to take on a trip or with me somewhere I'd rather not bring a computer.
I only really use them a lot before the draft has begun to fully take shape.
I'm flipping through a couple to offer examples.
The first includes: a personal Christmas shopping list; brief character sketches (like "latter-day hippie; new girlfriend; heroine's legal guardian; pushing 30); physical descriptions ("insurance salesman in business casual"); first drafts of scenes; an interview with a source (public information officer for a police station); possible chapter titles (of a pithy thematic nature); notes on a place I visited as a possible setting model.
Other second has more of the same plus notes on the history of the genre in which I'm writing and a sketch of the protagonist's fictional bedroom.
For me, the benefit of the notebook is that it gives me a venue for getting something down so that it's less intimidating to face the screen. It's also portable and offers a good, easy to store reference for the process.
The downside is that it's totally disorganized.
Most of what goes into never reaches the manuscript except in the most tenuous form, but it still gets me to the point where the manuscript exists.
Back to work today: realigned the chapter breaks and adjusted the titles; expanded the author's note; drove over to South Congress to do a little shopping/research.