You're Correct!

If you are thinning your golf shots you are simply hitting the top of the golf ball so relax your grip.

One of the reasons you will hit the top of the golf ball is that you are holding the golf club too tightly and this is by far the main reason why the majority of golfers either have air shots, or hit the top of the ball and thin the golf shots. To stop thinning your golf shots, you need to work on relaxing your golf grip.

If you put your hands on to the golf club, take up your grip and get ready to hit your golf shot, just notice what number you think your golf grip is at. So if 10 is squeezing as tightly as you can, what number do you think your hands are holding the club at? The correct answer for the pressure in your hands should be about 4 out of 10. If you are not sure where this is, then squeeze as tightly as you possibly can and call this a 10. Now halve the pressure in your hands down to 5 and then just slightly ease off again, so that you have now dropped to 4 out of 10 and that is the correct pressure to have in your hands both as you start your swing and all the way through it. This pressure should be maintained at 4 out of 10 so that you are holding the club rather than squeezing it.

The main reason that holding too tight will get you thinning the golf shot is that when you are holding the golf club too tightly, you have to use the muscles in your arms and in your shoulders and as you are using these muscles they tighten. When your muscles tighten they actually contract and shorten. So effectively you are shortening the distance between you and the club head. You are pulling the club head up away from the ground, which means that as you swing the club back down to the ball, you are just hitting the upper part of the ball and thinning the golf shot.

Before you hit your golf shot, check your grip pressure. If you are not sure where it is at, squeeze as tightly as you possibly can and then just halve it. If you are on a 5 that is absolutely fine, 4 is absolutely ideal, but as long as you are in this ball park area for grip pressure, you are going to hit a much better golf shot.

If you straighten up and you lift out of posture during your back swing, you are obviously lifting the height of your head from where it started. If you are increasing the height of your posture as you swing back down, you are in a higher position than you were as you started and the club head is higher than it was when it started as well. You will now tend to hit the top of the golf ball.

If you have got more weight on your right foot than you have on your left foot, for a right handed golfer, the bottom of your swing arc will always tend to be opposite where your centre of gravity is. If you have more weight on your right foot and you are leaning back as you are striking the golf ball, the low point for your swing arc will be too early before you have got the club head to the ball and you will catch the ball on your up swing.

As the club head is travelling on an upward swing, you will be more likely to hit the upper part of the golf ball.