Concentration becomes easier
There is a quick point on concentration I'd like to make, after just observing the behavior in myself.
When you first try to concentrate on the present moment, by necessity you'll try a lot of "gimmicks", where the word gimmicks in this case is a good and necessary thing. For instance, when I'm struggling to concentrate on the present moment, I often say things like this to myself:
Be here, now.
Be right here, right now.
Where are you? Focus on what you're doing!
What am I?
When driving, I'll ask, "Who is driving?"
Master? / Yes? / Do not be deceived!
In the kitchen I have a little card on the wall that says, "Become One, Infinite Time, Infinite Space Buddha"
I might also take a few moments to focus on my breath.
Concentrating like this is also a struggle at first ... it's hard, it's effort, and it can tire you out. After a while you think, "I can't keep concentrating like this, it's wearing me out."
However, when you get really good at this, it becomes natural. When you pick up a glass, as I just did, it's only you and the glass. There is no thinking, "Focus on the glass!", it's just picking up the glass, drinking, and putting the glass down. A lot of times I close my eyes when drinking, at least when I'm alone, because I want to just focus on the smell of the drink (coffee, juice, or soda), and the feel of the fluid on my lips and in my mouth.
This sounds simple, but at first it takes effort, and it tires you out. But after a while all of this becomes very natural and simple, and it takes no effort. If that sounds like a contradiction, I hope you'll this in your own practice, and after a while see that I am right.
It's a good feeling when you reach this stage. You'll feel energized, because at the very least, you're not always questioning yourself. It's just you and the action of the moment.
No third-nen while pitching
I think I was lucky, growing up as a baseball player, specifically spending a lot of time as a pitcher. When pitching, there is no time for a third-nen action. It's just "Throw a curveball to the low outside corner ... wind up, keep focusing on that target, throw curve." There's no time for extra thoughts like, "Hey, check out that cute girl in the stands", or, "Oops, did I lean back too far? I think I did, maybe I did ... do you think anyone saw that I didn't lean back too far?"
Like when someone is on first base, you don't think, "Did I check that guy at first?", you just think, "Check that guy, check him, check him, okay, pitch."