You can’t “overcome” nerves on the first tee if “overcome” means shut down your body from the normal heightened state of awareness (what some call “nerves”) that every golfer should have on the first tee. You can eliminate “fear” on the first tee using four approaches.
1. Before you go to the first tee, practice the first tee shot on the range. Visualize it. Gain some confidence in what you plan to do on the first tee and if you cannot be confident with a driver or even a three wood or driving iron, hit something you can be relative confident in.
2. Stop thinking you and the first tee shot is important and you are being judged by others more on that shot than any other shot. It is of equal value to every other shot, including tapping in that putt that hangs on the edge of the hole.
3. Plan your shot for the fat part of the fairway or better side of the fairway and pick the tightest, smallest target possible, preferably a 3 yard square target at the largest to land your tee shot.
4. This is the most important – swing smooth, only 70% max and do not seek to impress anyone, do not hit is as far as you can, and do not try to alter your normal shot. If you usually draw the ball, go with that shot.