Yogi Berra once said, "Baseball is ninety percent mental and the other half is physical." You can apply the same theory to golf.
So, if I get nervous on the first tee, I mentally tell myself I am on the third hole.
My best true story about first hole nerves: Fuzzy Zoeller was playing a charity pro-am event at Oakmont Country Club. The unwitting amateur steps up to hit first, and in the middle of his back swing Fuzzy interrupts, "Hey, John! Wait! Stop, J-O-H-N!"
At that point John stopped his swing and asked, "What's wrong, Fuz?"
Fuzzy replied, "John, I just wanted you to know that I am a famous golfer and a lot of people come out to see me play. Look around. There are more people here watching you hit your drive today than ever in your life. Now go ahead, hit it a mile."
John's butt got tighter than a drum, but to his credit, John managed to hit his drive about 150 yards into the rough. Fuzzy knew he had John's goat, and for the rest of the round Fuzzy continued to find a way to push his button.
On a par three while everyone was watching John's shot land near the green, Fuzzy was moving the tee marker forward 5 yards. Once the ball settled just off of the fringe, Fuzzy quipped, "That was pretty good, John, but next time you might want to tee up behind these things."
All in all a fun day, unless you were John.