Oh, you're a firearms enthusiast as well! I'm impressed. I compete in pistol and three gun competitions. I own a Glock 22 gen 4 and a Glock 19 gen 5 as well as a Sig Sauer P228 for pistols and a Remington 870 12 ga. For bullseye shooting, breathing and focus are so crucial. In the zone I can see the muzzle flash, the spend shell eject and the slide cycle like its in slow motion. I take a deep breath and present a little high, let the front sight setting on the bullseye while letting out half the breath and then squeeze. For combat shooting I visualize the course of fire in my head to include drawing and reloads.
A former BF taught me some tantric sexual techniques with breathing and focusing on...things. I have to say it does good things.