I'll start writing once I've done the ironing or the Noble Art of Procrastinating
Make a realistic commitment. There is not point saying you will write an entire essay before dinner if you know in your heart of hearts that what you are really going to do is spend half an hour reading a magazine and half an hour in a blind panic meaning that you start writing fifteen minutes before you are set to eat.
Break down your task into "chunks" - list each section on a piece of paper.
Strike off items on your list as you write.
Start at a time you know you can work; I like writing late at night and any work I produce in the morning is total drivel.
Off you go! Good luck (and remember, a pot full of perfectly sharpened pencils does not contribute to your final grade!)