Your focus improves as your habits improve. The amount you have used that specific habit in competition in turn determines how comfortable you are when you are competing.
I was in a shoot-off with Olympic skeet shooter Matt Dryke at the first Beretta championships held in our country in 1987. While waiting to shoot off, I asked Matt how he concentrated when shooting at the Olympic level.
“Concentration is the art of thinking about nothing!” Matt said.