I put numbers in my clothing. For example, If I had four pair of sanitary hose, they would be numbered 1-4 as well as for left or right. Heaven forbid I put a left sock on a right foot! We can not have such anarchy. If I had a good outing, I would always wear those exact articles of clothing until my luck turned.
I would get a can of orange Crush from the vending machine at school and put it in my bag before heading to the field or the bus. When we got to the field, I would drink the entire soda during the short walk to the bench and while I put my spikes on. It always relaxed me, even with all the sugar.
During warm-ups I would have my Walkman attached to the back of my belt and I'd throw with my headphones on. If I got in trouble or out of sync on the mound, I would just think of one of those songs I heard before the game and just throw.
Another thing I would sometimes do when stressed on the mound is bring the palm of my glove up to my face, place the ball inside it and, with my eyes closed, I would breathe deeply the smell of leather and dirt. When I opened my eyes, my mind was clear.