One of the most pervasive problems among poor putters is lack of speed control. Moreover a large percentage of the bad speed control comes from a non-accelerating motion in which the putter head decelerates through the stroke.

 To develop an accelerating putting stroke:

Lay a 2" x 4" board up to the hole. Place a golf ball at the end of the board. Next place the putter directly behind the ball with the heel of the putter resting against the board. Practice pushing the putter head along the board onto the hole. Use no backswing!  Push the ball into the hole. This drill accentuates an accelerating and straight-back and through motion.