The trick to speed and precision is simple--it isn't just practice, either--you have to reconsider and rework what you're doing continuously, as JP mentioned, there is a lot of extraneous movement that most people have in their playing, and you have to eliminate as much of it as possible--Planning is also critical--one of the biggest drags comes from not really knowing quite what and when you are going to play--Another thing to remember is that a lot of music is overwritten--that is, it has too much stuff in it to be done with any speed--