There are a number of ways to build the clubhead speed necessary for good distance as well as optimum trajectory. The right one depends on each player's physique. If you don't have the hands and forearms of a blacksmith, you can't rip the club through impact like an Arnold Palmer or a Hal Sutton. Nor can you copy super-supple Tour pros like Greg Norman; he "torques" his upper body, turning it against his resisting hips to build tension in the midsection that uncoils on the downswing.
What you can do for more power is turn your hips freely along with your upper body on both the backswing and the downswing.
Backswing Turn

Any number of keys will start the club back
effectively. Some golfers push it back with their left
arm, some drag the clubhead back with both hands, others
turn their torso clockwise. Whatever key you prefer,
remember, as you turn your upper body, let your right
hip turn with it. The drawing above shows that the
player's hips have turned to the right nearly as far as
the shoulders. This free hip movement builds the
momentum for the downswing. If the hips were to remain
in the address position throughout the swing, you
wouldn't get much of an upper-body turn and you'd strain
the abdominal muscles. Allowing your hips to turn leads
to a full body pivot.
The hips must turn in a circle. Don't sway them to the right -- that makes returning the club squarely to the ball difficult because you'll have to make the same amount of sway on the downswing.
Clear on the Downswing

On the downswing, turn -- don't slide -- your
hips counterclockwise. At impact, your hips should be
turned slightly past the address position. This turn
gives the hands plenty of room to move and release the
clubhead so it squares up at impact and then closes
beyond it, which helps you draw the shot for additional
yardage.
Sliding rather than turning the hips toward the target makes them square to the target line at impact. This action "blocks" your hands from releasing. The result is a high, lazy shot that drifts right and sacrifices yards you can't afford.
Let your hips turn clockwise going back and counterclockwise through the downswing. You'll get a freer, fuller backswing turn with the room you need to release through impact.
Private Lessons 1999 Time4 Media, Inc., used under license by GolfServ Online, Inc. Instructional information provided by Golf Magazine.