High handicappers can only control the line and speed of their putt, and according to Phil Blackmar, poor speed control is the cause of most putting problems for high-handicap golfers. He demonstrates an easy drill in this video golf lesson, called a ladder drill, which is greatly beneficial to high handicappers in controlling the speed of their putt.
The drill involves taking a series of practice shots, pitching the first putt about five or six feet from you and then hitting each additional putt an extra three feet further. Making these practice shots will give high handicappers a feel for the movement and distance, allowing them to better control their speed.