There are a myriad of tips and aids to help the golfer aim the putter and stroke along a correctly aligned path, but snapping a simple chalk line for a five foot putt is my favorite. Even a golfing friend can stand behind the line and tell you if the putter is aimed properly and on the right path. But not enough players will invest in a putting lesson, where a good teacher can tell you if your shoulder alignment, stance, or ball position is wrong–for you–and fighting the best of your efforts.
Personally, my shoulders tend to creep too open over time, creating a tendency to pull putts, but slightly open shoulders are my “norm” when putting well. Square, open, or closed….one man’s food is another man’s poison. But a faulty stroke can mean something in your set up is amiss, and all the concentration on aim and path won’t produce results until the set up is corrected.