Once the take away in completed, making a correct shoulder turn not only helps produce your maximum distance but also helps keep the ball from straying into the rough.
After the original takeaway has occurred simply concentrate on rotating your shoulder under the chin to a position directly over top of your back knee (i.e. the one farthest from the target). When done correctly this will result, from a proper setup position, in a 90 degree turn of the shoulders and in turn, because of the way the human body is constructed, a 45 degree turn of the hips. This full turn creates a very powerful swing in two ways.
It builds up tension in the back, abdominal and leg muscles. This tension is released during the downswing creating club-head speed in direct proportion to the amount of tension created in the turn.
It places the majority of the players body weight on the back foot ready for the forward transfer to occur. As such, the golfer uses his/her own body mass to create additional power.