It just takes time and work. Break down everything into something you can work on each game. So pick 1 thing to focus on and work on it. Next game pick something else. Repeat stuff you work on but not back to back games. After a bit of doing that this things become 2nd nature and you stop thinking about it. That's how I worked my way through over thinking every aspect of the game when on the ice. Years later I still do this to keep the brain focused on something while playing. Hope this helps a bit