Keep a clear mind when practising and remember that a good swing is a combination of a lovely grip, stance and posture and the way you position your body in relation to the target. If all is done correctly the chances of hitting a good shot will drastically increase.
The differences between a good and average player we all notice immediately. You will hardly see a good player with a bad setup or a bad player with a good setup. A good player looks relaxed and ready to go, in contrast a bad player looks stiff & tense. A good setup with everything in place is very important if you wish to play some good golf. Even a slight defect reduces your chance of hitting consistently good shots. What a good setup will do is help considerably your balance when all components of the swing are set in motion. It's no secret that good players spend a large proportion of their practice time focusing on their setups because they know that it's the surest way to hit consistent shots.
Use a mirror and keep checking that everything is in the correct position. Fight against the fear of having to make a change, as initially it will feel uncomfortable and take a while to get familiar with. Seeing, as well as feeling, is reassuring. Work on your grip, stance, posture and alignment everyday if you can -- even if it's just for a short time. This will test your patience but eventually all previous stresses will disappear of making good movements through the ball. There are no excuses, our bodies are all different tall, thin, fat or short but with practice we can all look good when addressing the ball.
Out of Bounds: There is no more miserable human being than a golfer, who considers themselves useful at the game, having just made a double bogey.