To be honest besides supplements to stay awake and going all night the number one way to focus is... Caring. If you want something badly you don't get distracted.
Sports are a great example.
You don't care if the crowd is booing, cheering or heckling you, the only thing you see is the goal/hoop/target.
It's relatable to game, you don't see fat girls because you don't care about them, you only see the good looking ones. Focused.
Similarly nervousness is just the same. If you flutter in sports or "choke" this is really just caring about "what if you miss" lost concentration. The best people have unyielding abilities to focus in on what they want.
Sports are a great example.
You don't care if the crowd is booing, cheering or heckling you, the only thing you see is the goal/hoop/target.
It's relatable to game, you don't see fat girls because you don't care about them, you only see the good looking ones. Focused.
Similarly nervousness is just the same. If you flutter in sports or "choke" this is really just caring about "what if you miss" lost concentration. The best people have unyielding abilities to focus in on what they want.