Quietly working away. All the preparatory drawing is supposed to help plan out the color, composition etc. For me it also works as a way to get me excited enough with the prospect of making a painting that my fear of failure will abate. I will delay, and find any reason to procrastinate, but if I start casually working away in my sketchbook (pretending it's not a serious thing afterall...lalala...) , nothing will stop me unitl I drop. So I actually trick myself into working...How do you start something?