Improve your putting by focusing on short and really long putts!
When practicing putting, the average golfer tends to grab 2 or 3 balls and putt around the green, trying various 15-25 foot putts. He putts the balls fairly close to the hole and then either taps the remaining 6-inch putt in one-handed or just moves to the next hole. The problem with this is the golfer never hits the ball into the cup! May sound like a silly point as he is still having to judge pace and line to get the ball close, but practicing this way trains you to putt the ball close, not in!
I recommend practicing putting just two different lengths – very short 2-6 feet and very long 40+ feet. By practicing short putts you will build an accurate stroke and gain a lot of confidence over short putts, which will in turn lead to more confidence over medium-length putts. By practicing very long putts you will work on eliminating 3 putts by being a better judge of pace and green reading.
Working on these two lengths of putts will make you a better all-round putter. The best thing about practicing the shorter putts is that you see the ball roll into the hole time after time. This helps so much when you are put under pressure.