Does this sound like you?…
You feel a lot of tension in your golf swing and you try to tell yourself to relax but the harder you try to do this the more tense you become.
If this does sounds like you the first piece of advice is to not “try.”
Because trying creates tension in your golf swing so cut that “trying” out first.
Next you should go out to your driving range and simply hit balls while humming quietly to yourself. When you’re doing this focus on your humming and notice if it stops or changes pitch at any time during your golf swing.
Just keep hitting balls focusing on your humming with the goal of swinging without the hum changing pitch or volume from the moment you start swinging to the end of your golf swing. But please don’t “try” to achieve this. Simply keep swinging and focusing on your humming, and soon without you noticing the “whys” or “hows” your golf swing will become more rhythmical and less tense.
Once your golf swing is more in tune with your natural rhythm you want to keep it that way. Do this by having a few golf swings each day while quietly humming to yourself. Doing this will help you to have a golf swing with less tension and consequently you’ll hit the ball further and more consistently.