Until I am next up to shoot I let my mind wander where it wants to go, I used to do this in cricket when I was batting. In between overs we would be planning our night out, comparing who we pulled last night, anything but cricket. As soon as the bowler reaches his mark I used the "Show-time" you will read later as a trigger to switch on.
When the guy in front steps onto the pad (skeet) I am staring at the floor (blade of grass, daisy, lump of clay, anything really) saying "Focus" to myself nearly as a mantra. When they have shot I step on and I say "Kill one at a time" while picking out my hold points. Then I load my shells and as I close the gun for the first bird I say "Show-time" Obviously this is all said in my head, I'm not that much of a lunatic :lol:
These are my key or trigger words so might not work for everybody but they seem to work for me. The only time I need to reset is if there is a no bird. Then I will break the gun and repeat "Show-time" as I close it again
You should have to reset, (or in my case, set) yourself multiple times through a round as its just not possible to be at peak concentration for that long. Let the mind wander between stands/stations and set yourself just before you are up to shoot