Do you really want to get good? Then do this:
  Before every putt, stand behind the ball, face the hole, and imagine the path the ball will take on its way into the hole. "See" the ball go into the hole, and "hear" the sound it will make as it clanks to a rest in the hole. Imagination is very important in golf.
  Then take two or more rehearsal strokes while looking at the hole. Rehearse exactly what you intend to do (note: you may stand to the side of the ball rather than behind it, if it feels more comfortable). Don't practice your mechanics. Try to feel the stroke required to make the ball roll the proper distance. While you make these "feel it" rehearsal strokes, again imagine the ball rolling into the hole. You are creating a connection between yourself and the target, not practicing your stroke. The more clearly you can "see it" and "feel it," the better your connection will be. Get this point straight: Practice strokes are for working on your mechanics. Rehearsal strokes are for making putts.
  While standing behind the ball, (you have not yet addressed the ball) pick out a small target, such as a blade of grass, that the ball will roll over (or toward) on its way to the hole, and lock that target in your mind. Try to see a path from your ball to the target.
  Step up to the ball and aim your putter. Next, align yourself (take your stance) to the putter. Then run your eyes back and forth along the line to the target. Do this "tracking" with your eyes slowly, and try not to let your eyes "jump" along the line (that will take some practice). Then, when your brain tells you that you are ready, putt the ball. If it goes in, go take it out of the hole. If not, repeat the process.