Variations on a theme by Annie Dillard
When you are writing, you know what you need to do. Making sure your pencils are sharpened and lying parallel on your desk, wiping down surfaces because the sight of dust grates on your skin, reading things you think have nothing to do with what you're writing, taking a nap at the wrong time, calling a friend to rant about your dissertation's bad habits and poor hygiene: all of it. I don't mean to honor procrastination, but rather to honor ritual, gathering, and acts of desperation. Procrastination is turning your back on your work, telling it to sit in the waiting room until you are ready to deal with it, and hoping it will get bored or angry enough to just go away. Percolation is confronting the empty plot where your work should be, digging away at it until you realize you need an awl or a pick-axe or a backhoe instead of the shovel you've got in your hand, and going off to beg, borrow, or steal the right tool for the job.
The trouble comes when you stop confronting the work and stop listening to yourself. And you learn this every time you start something new, then forget it again, so that beginning is always a terror.
The only hope is to be stubborn enough not to quit before you learn the lesson again--and to believe that you'll remember more quickly next time, even if you never do.