Do you three-putt a few times during your round of golf? Are you the one who hopes your playing partner gives you that 3-footer? No such luck in a tournament. Try this exercise: place yourself on the green without any club (including the putter) and try to put the ball in a hole that is 25 feet away from you. Well, I guess you will face that hole and toss the ball underhand toward the hole. So why don't you putt that way?
Practice using a perfect lie to start with. Start by learning the basic before trying from the bunker.