...as gleaned from from Da Capo Press' 2009 book Heroes and Villains: Essays on Music, Movies, Comics and Culture* by David Hajdu, author of The Ten-Cent Plague (Hajdu's piece quoted from below—everything in italics is him—was originally published in the October/November 2004 issue of Bookforum)
1.) BE LIKE A LIZARD
"Emile Bravo told me, 'When you are drawing, be like a lizard—be perfectly still, but aware of everything around you. Don't waste your energy with a lot of movement while you're working. Be like a lizard.'"
2.) DRAW IN INK
Dispensing with drawing-class convention, she uses a marker rather than pencil; the ink, being less forgiving, "forces me to concentrate," she says. "Otherwise I would sit here all day and draw shit."
3.) USE CHEAP PAPER
She draws on the most inexpensive paper she can find. "If I use very good paper, I feel like I have to make a masterpiece," she says, "and the best way to make shit is to feel like you have to make a masterpiece. I feel now like the world is waiting for a masterpiece every time I put a brush in my hand, and that is a bad thing. Cartoonists shouldn't have to be too good."
*Mostly music, though. By my count, only four of the 40 articles collected in the book are about comics or comics creators.