Roll the Ball line over line
The one question I ask myself after every putt is not “did it go in?” but rather, “did it roll line over line?” By that I mean, did the ball have a smooth roll, end over end (or head over heels). This is a great way to test the purity of a putting stroke and is relatively simple.
First, draw a line all the way around the golf ball.
Then set up to the putt lining the line of the putter so that it nearly touches the line on the ball (other wise known as square impact).
Finally test if the line wiggles or spins completely around. If so, this meas that the ball is rolling on a titled axis and isn’t moving “head over heels”. This is an indication that the putter face and path are out of sync or that the tempo of the stroke is off. It will be tough at first, but once you get the hang of it, you will find that the line on the ball will find the bottom of the cup.