From the First Tee
How the Eyeline Putting Mirror Fixed My Aim
If there is one thing to know about putting, it's that the angle of the club face (where the face of the putter is pointing at impact) when you strike the putt is far and away the most important element of being a good putter. Even if your path is not perfect you can still make a fair number of putts if your putter face is perfectly aligned to the proper path of the putt. In fact, according to this study by Science&Motion Sports, makers of the SAM PuttLab, 83% of the direction a ball will take coming off your putter is attributable to the putter face angle at impact. So generally the ball is going to go where the putter is pointing. Sounds simple, but you'd be surprised how often this fundamental is overlooked.
When you watch the tour pros make 59/60 putts from inside 5 feet you find it mind boggling. Of course they have fine-tuned their strokes to match up the proper face angle and path (the other 17% of putt direction) to the tiniest of variances. In fact the renowned teacher Ralph Maltby has estimated that tour pros "have developed the skill to align the putter face angle to the intended line by less than ½°." So the best putters know that the face has to be precisely aligned at impact to be a great putter. In fact you will miss a putt of just 5 feet if your face is open 2 degrees at impact. Think about that, 2 degrees isn't much at all.