One of the keys to my technique on the green is my posture.
I like to feel that the top of my back is parallel to the ground. From here my arms hang freely down allowing me to swing the putter back and through along a straight path that keeps the putterface square to the target for longer.
There are lots of players who prefer to swing the putter on an arc (from inside the ball-to-target line to square to inside again) as their arms move around their body but I favour a straight back and through stroke. As the face is square to the target for longer, I feel that this technique increases my chances of hitting the putt on line.