I've coached Paul Casey since his first year at Arizona State University (1997) and I can tell you that he's a great kid. People who think he's cocky or too brash don't know him at all. I also can tell you that he's one of the most controlled power players out there on Tour. Actually, he's one of the top two or three in the world at combining power with control.
How does he do it? Well, it helps that he's strong. His forearms are gigantic and his legs are like pistons. It also helps that he's always focused on improving his game.
When Paul and I work together, we check his basics: grip, posture, balance and swing shape. Everyone should be focused on improving these areas, not chasing the latest gimmick to come down the road. Fundamentals are why Paul has improved every year, and it's how you can too.