You are a winner. Start acting like it. Whether you're playing with your friends in the park scrimmaging at practice or competing in the championship final. Play to win and do your best in every moment. Refuse to lose every match drill and individual battle.
This actually made me cry. One day it will be a memory, embrace every stroke, kick, breathe you take because one day, you'll be looking back at all those things you did and wish you could do it just the same.