Finding your Dominant Eye
Select a small focal point a few yards away, such as a small figurine on a nearby table. Keep both eyes open.
Make a circle with your thumb and forefinger. Hold your hand out at arm's length and encircle the focal point with your thumb and forefinger.
Close your left eye, then open it and close your right eye. If the focal point is still encircled when your left eye is closed, you are right-eye dominant. If it is encircled when your right eye is closed, you are left-eye dominant.
Move 3 to 5 feet away from the ball, with the hole behind the ball. Make sure you can see the hole clearly. Line up your dominant eye with the hole and the ball so that all three form a straight line. Straddle this imaginary line with your feet shoulder width apart.
Close your non-dominant eye and hold your club at arms length just below the grip, with your thumb and forefinger. The club should be directly in front of your face. Let the club hang straight down, and allow the shaft of the club cross over your ball.
Examine the position of the hole with your non-dominant eye closed. If the hole appears to be to one side of the club shaft, the green may slope in that direction. If the hole is in line with the shaft of your club, then the green does not have a significant slope from the ball to the hole.
Compensate for the slope by putting slightly to the opposite direction. In other words, if it appears that there is a slope to the right, aim slightly to the left.