Sometimes I avoid writer's block altogether by researching and researching and researching and researching.
I do loathe staring at a blank screen. The best way for me around that is to write morning pages as described in THE ARTIST WAY. I keep blank pink paper (white with lines is too intimidating), a pen and a lap desk next to my bed. When I wake up in the morning, I pick up the pen and scribble whatever is in my head. Yes, I write by hand. I actually draft all my books by hand now. This process short-circuits my inner critique and taps into my inner artist and coaxes her out to play.
I recommend working through THE ARTIST WAY (Julia Cameron) to every writer and artist I know.