I've had to practice PF for a while because I'm myopic.
What I do is, I write a | | shape on a window, then I practice training my eyesight at the surface of the glass, then right through it at objects at various distances from 20 feet, to 100 feet, to a block away, to the horizon. The further I cast my eyes away, the more the shape on the mirror goes into PhotoFocus and the | | turns into | ||. That's how I know I got it. I do this as many times as I can quickly so I know how my eyes feel going directly into PhotoFocus.
It's still hard because training eyes that far is hard for nearsighted people; it's stressful to stare but without staring you don't see the object clearly. But sometimes my eyes tear, then it pops right in clear as a bell, and the PF is right there.
