The best way to overcome nerves is with the same strategy you would implore in a negotiation.
Step 1: Acknowledge the feelings/thoughts and gain awareness. Say to yourself “I know I am nervous and I sense how this is making me feel”.
Step 2: Make the feelings ok and reassure yourself. It is okay to be nervous because you care about this situation. “It’s okay to be nervous because I care and want to get off to a good start”.
Step 3: Change course (refocus) and move the feelings to the appropriate place. “For me to get off to a good start, let’s pick my target, visualize my shot, and focus on my breathing”.
I often hear people chastise themselves for getting nervous or focus too much on the nerves themselves. Let’s not empower the nerves but acknowledge and respect why they are there. It’s because you care about what you are doing. Make that okay and then acknowledge, reassure and refocus to help deal with those 1st tee jitters.