Funnily enough, this is how I managed to start beating my best friend at chess, who reliably beat me every game previously for 2 decades.

One day I just started making somewhat random moves (not terrible obviously, but unusual, and which sometimes gave me a temporary disadvantage). This completely messed with his style of play. He was trying to figure out what my grand strategy was I guess and tied himself in knots. From that moment, I could often beat him.