Base stealers should study the opposing pitcher the moment he takes the mound. Watch the pitcher throw to the plate from the stretch. Note what body parts he moves first and whether he does anything special when he throws to first base. See if he sets his feet up differently on his pick-off move. Try to detect any quirk that will reveal the pitcher's intentions.
Good pitchers are often the easiest to steal on.
You never know when they are going to let go of the ball. The better pitchers have purer mechanics. They establish a rhythm and stick to it. Boston's Pedro Martinez will do the same thing to get to his release point on nearly every pitch. So you may be able to spot some clue in his motion.