I have never given a first time lesson (especially to a beginning golfer) and not addressed a grip and or posture issue. Beginning golfers try all the time to keep their heads still or down (which is total nonsense). Most beginning golfers also try to keep their arms very straight (which leads to very rigid stiff arms). By getting someone into good posture and a grip that is more into the fingers and not in the palms we fix both of the above issues and it is amazing how quickly the ball gets into the air and flies straight. Teach a beginning golfer how to put hook spin on a golf ball and they will have a lot of fun and you will have a student for life. You cannot hit it straight until you learn to put hook spin on a ball first.