Anne Lamott says:
I believe in lists and I believe in taking notes, and I believe in index cards for doing both. I have index cards and pens all over the house—by the bed, in the bathroom, in the kitchen, by the phone, and I have them in my glove compartment of my car. I carry one with me in my pocket when I take my dog for a walk.
Anne Lamott, Bird by Bird: Some Instructions on Writing and Life
So here’s what I’m doing:
I’m using these 3×5 cards from Levenger (mostly because I already had them), and keeping them handy so that I can write down notes and scenes for HOUSE RULES as they occur to me.