Setting the club correctly at the top of your golf swing will allow you to swing back towards the ball more efficiently and with a faster club head speed as you will not need to waste energy correcting the club position or trying to get it back on line.
The correct position for a well set club at the top of the backswing is as follows.
Rotate your shoulders 90 degrees to the right (for right handed golfers). Extend your left arm so that it remains straight and achieve a head height position with your hands. Your club should be just above horizontal and it should be pointing parallel left of the target.
If you achieve this position at the top of your backswing you can now accelerate at full speed into impact and the club will move very efficiently and easily into the ball achieving a solid connection from the middle of the club face, with the club face square to the target as you strike.