Start the lift with the feet slightly spread to about shoulder width, knees bent as shown, the back straight and the head up. The feet are flat--you should not be up on your toes.
As you start to lift, keep the shoulders level and over the bar while keeping the back straight. Maintaining the shoulders directly over the bar is very important. The feet should still be flat.
When the bar is raised to this position, it is critical that the hips be pushed forward. This is the beginning of the explosive part of the lift.
As you get to this point, rise up on your toes and shrug the shoulders up and in toward the ears. This called the "shrug".
At this point, pull the bar as high as you can and in toward your chin. The bar should be close to the chest, but should not touch it.
Then with a quick thrust, push the elbows out and pull the bar closer to the chin. Note that the knees are still bent. As you rack the bar, the feet should be spread slightly wider apart to where they are about under your hands.
The final movement is to rack the bar as high as possible on the shoulders while going to a full upright position.
(Above pictures are from a video that I made at an AAF/CIF coaching clinic at MT SAC)
(Above pictures are from "IRON MAGAZINE")
MORE TO BE ADDED