Putting consists of three main factors: Break, Speed and Aim. You need to be able to read the correct break, hit it the right distance and aim the putt on the intended line. If any one of those three factors is off, you won’t make the putt. The first 2 vary from green to green and putt to putt. There are so many variables like slope, grain and stimp that being able read every putt perfectly and get the speed right every time is near impossible, even the pros with caddies can’t do that, but you can get the ball started on the right line every time with a little practice. If you train your aim, at least things will start in the right direction. That is where this training aid comes in, it is a simple way to learn to aim better.
I think the first off is getting a putter that fits your eye, because even with the most advanced training aid, once you are on the course, that putter has to function all by itself. Make sure you have the right kind of mallet or blade that fits your stroke and your eye. Then Train Your Aim will be an even more useful training aid.