Try the five-star plan

Next time you're on a practice putting green, try this drill: Pick a hole that's got some slope and some break. Then get out five balls and place them all about three feet from the hole, as if they were the points of a star. This will give you every type of putt you'll encounter – left-to-right, right-to-left, uphill, downhill. Once you can make all five, move back to four feet and so on until you believe you can make everything.