In other words, when taking signals from the third base coach, the runner should have a foot on the base. Too many kids get picked off because they are watching their coach give signals while standing off of the bag. Furthermore, a player should always watch the pitcher when taking a lead. Someone said your lead should be a body length and a step and this became the standard. A better rule might be on your first lead, go with the body length and a step, wait for a pick-off attempt, and evaluate your lead.
Some pitchers have quick moves, while others are rather slow.
A base runner must take advantage of every opportunity. As far as technique in taking a lead, there are several different methods. I instruct my players to take a crossover step behind the right foot, followed by two sideways steps. This is a good base to work from and the lead can be extended or shortened from there. The player should take his lead at the front edge of the bag.