How do you play a perfect piece of music?
Play the whole piece very loudly, then very softly, and then somewhere in between. This helps improve your control of volume. Next, identify different dynamic levels in your piece. Play the sections out of order, starting with the quietest section and ending with the loudest.
How do I practice fast pass?
Another way of practicing fast passages is to start playing it as fast as possible, or at the final speed, making sure that your muscles are completely relaxed. Memorize the movements involved, and practice slowly but with the same movements you memorized when you played or tried to play fast.