You can see the same small, dark grass area next to the hips when Tiger is at the top of his swing and at impact. Amateurs often push their hips toward the ball on the downswing, which inhibits a free-flowing swing and forces you to alter your path. Tiger rotates his hips, and has maintained the same distance from the ball on his downswing that he had at the top.
Here's how to get a feel for rotating your hips toward the target as opposed to sliding them out. Stand your golf bag behind you and press your butt up against it as you take your address. Now hit balls while maintaining contact with the bag at all times. Your right cheek should be in contact with the bag at the top, the left cheek in contact at the finish.
Contrary to conventional wisdom, Tiger does not delay the unhinging of his wrists for as long as possible. As soon as he initiates his downswing, he starts rotating his left forearm. That action starts to square the face and begins the gradual release of the clubhead. Halfway down, his wrists are already uncocking.
Create a feel for a gradual release by hitting shots with only your left hand. This will encourage you to rotate your left arm throughout the downswing, since you won't have enough power to snap your wrists through impact. Hit five shots one-handed, then use both hands and duplicate the feeling of a gradual release, the left forearm rotating counterclockwise through impact.