Many say the 4 biggest putting mistakes are poor stability, bad rhythm, inconsistent face control and under reading greens.
Golf allows 2 putts per green. Tour player's average 2 putts from 30 feet while single digit handicappers average 2 putts from 25 feet, those who score under 100 average 2 putts from 19 feet and those who score over 100 are only able to 2 putt from 12 feet.
To be a good putter, you must first have good pace by eliminating all lower body movement for better stability. Close your eyes during practice strokes to heighten your feel for improved stability. A good practice drill is putting with a ball wedged between the end of the shaft and the wrist for improved stability.
I constantly have students ask me about the one third to two thirds ratio. Many golfers believe this is about the length of the putt stroke. They believe the back stroke should be one third of the length of the entire putt stroke while the length of the forward stroke is two thirds of the length of the entire putt stroke or a 2 to 1 ratio defined as the forward stroke being twice as long as the back stroke. This is completely wrong because the length of the stroke determines the length of the putt.
The one third two thirds rule or 2 to 1 ratio is about rhythm. The back stroke should take twice as long as the forward stroke. Use the 1, 2, 3 practice drill. On the back stroke, you should count 1, 2 then on the forward stroke count 3. The result is the back stroke is two thirds of the total amount of time it takes for the total stroke while the forward stroke is only one third of the total stroke in terms of timing.
Face angle at impact has an 83% affect on where the ball rolls versus path direction only having a 17% affect on where the ball rolls. If you have a tendency to pull your putts, it typically means your face angle at impact is closed. If you have a tendency to push putts, it typically means your face angle at impact is open. A great practice drill is to lay down an alignment stick on the opposite side of your tendency and try to putt down the alignment stick. For example, if you are constantly pulling putts because of a closed face at impact then lay down the alignment stick on the outside of the ball and practice putting down the alignment stick.
Most recreational golfers under read greens. The best way to read greens is with your feet. In Southwest Florida, I work with a lot of seniors who have vision issues. If they only relied on being able to see the break, most would become frustrated. That is why I teach my golfers to be multi-dimensional. Use your eyes of course but also learn to feel the bottom of your feet. Walk to the middle of the putt and feel the weight shift on the bottom of your feet. Lastly, play more break than you feel because most recreational golfers under read putts.