The common thread of good putters is they consistently have the putter face square to their intended line at the moment it impacts the ball. Although putting is certainly the most individualistic component of the game you'll find the best and most consistent putters use a pendulum type stroke. Using this method the triangle formed by their arms and shoulders at address stays intact through the stroke.
When we lose confidence in our putting we start trying to “help” the ball in the hole resulting in our head and body moving out of position. This disrupts the alignment of the putter face leading to inconsistent contact with the ball and little control over the direction or speed of the putt.
In general the fewer moving parts in our putting stroke the more consistent we are. Developing a shoulder stroke pendulum action minimizes those moving parts.
To feel this stroke take your stance then place your palms together forming a triangle with your hands, arms and shoulders. With a steady head and lower body rock your shoulders so that you move the triangle back and through. Make sure to keep your chest square to the target line rather than opening your shoulders and body to the hole.
Your left shoulder should work down on the backstroke and up on the forward stroke. Your shoulders now control the path of the putter head and keep the putter on line through impact. A good habit for shorter putts is to not look at the hole until you hear the ball fall into the cup.
If you're struggling with your putting spend some practice time with this method and you'll soon be making more putts and shooting lower scores.