To get the machinery started I like do a little random drawing. Things I see around me. Still lifes of kitchen items, fruits and vegetables, knives and forks. Forks are trickier than you think. Hands aren't easy either, as I've mentioned before. I used to hate drawing them, mostly because I was bad at it. (Interestingly, I saw a stock-house illustration in the paper yesterday that had the left hand at the end of the right arm, and vice versa. I don't think it was intentional.) I've gotten pretty good at hands since then. One thing I've discovered, though, is the more perfectly drawn they are the less they suggest. An awkward drawing always works better at conveying metaphor, probably because our eye stops and tries to make sense of it. The less distinct it is the more it might be something else.