I used them to get my honors thesis written in a week-and-a-half. Just the actual writing, mind. The research took months. But getting everything written out on cards allows you to move things around. I recommend different colors for different characters' individual arcs as well as the overall story plot and subplots. Add or subtract cards as necessary. I prefer physical because I'm a historian and we're mostly all hopeless Luddites, but there are tons of lovely online programs that'll do this. My local NaNo group has some people ready to sell Scrivener door-to-door on a volunteer basis.
-Quaddy

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