Golf is very much a solo sport where, again as Bobby Jones pointed out, you soon learn that your most potent adversary is yourself--not your opponent, or the golf course, but rather yourself. To play the game well you must develop an understanding of the golf swing in general and your golf swing in particular. There is only one absolute when it comes to golf. That absolute is that a ball struck squarely in the back, with the clubface square to the target and moving straight down the target line, will fly straight, unless affected by wind or mud on the ball. You can be certain of this result.
The thing a golfer must learn is how to strike a ball in this way. It is really all about the strike. Consider what Bobby Jones wrote in his book Golf is my Game when discussing the backswing:
"The swinging of the club back from the ball is undertaken for the sole purpose of getting the player to a proper position for striking. So the one influence most likely to assure a satisfactory progression of the swing is the clearly visualized contact between club and ball still at the forefront of the player's mind. Just as the backswing should not begin until this picture is adequately established, so the movement should continue until there results an awareness that the player has become capable of striking in the intended manner.
I stress this point, and intend to continue to do so, because I know that the unrelenting effort to play golf in this way can do more for a player than anything else he can possibly do. When every move of the swing is dominated by the determination to strike the ball in a definite fashion, the complicated sequence of movements must acquire purpose and unity attainable in no other way."
This is the secret to the game. One must learn and understand how a ball must be struck in order to make it behave, and then one must swing the club in such a way as to assure that strike. Bobby played that way, confident that, if he focussed intently on the strike, his swing would take care of itself.
Sounds simple, doesn't it? To hit a straight shot all you have to do is hit the back of the ball solidly with your clubface square to the target and moving down the target line.
I remember the day Steve finished a round and was absolutely disgusted. He had been hitting the ball all over the place and asked me to watch him hit some shots on the range. He wanted me to try to tell him what was wrong with his swing.
I stopped him before he could hit a ball and bent down to the golf ball. Using his clubface I moved it a foot or so, from a few inches behind the ball stright down the target line. I then said, "Make the club strike the ball like that."
I stepped back and watched him hit the straightest, most beautiful, seven iron I'd ever seen him hit. He looked at me and just shook his head. When he focussed on how he wanted the clubface to behave, he was quite capable of doing it. Golf is all about concentration and focus.
So, what should you focus and concentrate on? Well, I'm not a teacher either, but Bobby Jones said it must be the strike. And I don't think you can argue with that logic. It only makes sense that you visualize and concentrate on striking the ball as it must be struck. It beats the hell out of thinking about your backswing.