Well, When I think about one of the greatest swings in the game of golf I think of Jack Nicklaus. The precepts that he used to groove his swing is a foundation to which I build my thoughts of teaching.
In Jack's classic swing, Jack set up more on top of the ball, with his right leg angled inward. He said as he got older that his body was not able to make as strong a lateral move to the impact position. his chin is still slightly turned to his right, allowing him to make a bigger shoulder turn. Jack always wanted his chest and his shoulders to react to the swinging of the arms and club during the transition. Note Jack replanted his left heel toward the target, which kept his hip from opening too soon. (Golf Digest, VOL. 58, NO.10)
Because of this principle of the body and shoulders needing to react to the swinging of the arms, I would insist that pulling down the club with the left hand be the initial motion to trigger the golf swing.
Jack always kept the arms in front of the body because everything else followed. This method of the arms staying in front of the body allowed him to never get "stuck."
Jack also used a technique he called rolling his ankles to control the rhythm of the lower body. He always maintained his feet on the ground from the transition at the top to the impact zone.
The principles I believe in are feet on the ground and hands in front of the body. It is quite simple but it really gets the job done quite nicely.
