The puttingzone is a great site. What really improved my putting the most?
Alignment putterface/ball to hole. I stand behind the ball and pick out a blade of grass 2 or 3 inches in front of the ball on a line to where I want to hit the putt. I get into my stance and align the putter face to the blade of grass. Look once at the hole, think/feel speed and swing. Simple and effective.
I am not good enough to use the dimple method on both sides of the ball yet. Or a blade of grass in front of and behind the ball. With practice I will get there. You can also use this method for all other shots as well.