Posture: Starting from an erect position the ideal posture for golf is obtained by doing a canter-lever action, moving the shoulders forward and the hips backward. The final position has the arms hanging straight down from the shoulders and the shins on your legs still in a vertical position.
By running your thumb up your back toward the neck, you can understand that from the hips to this point should be straight and from the thumb point to the neck can be a slight curve.
Another way this can be achieved is with a gripped club; raise the club and your arms up until they are fully flexed over your head and down your back. From here lower the club down until grounded. This method ensures that you are standing correctly and the correct distance from the ball.