Lol, just go cross eyed and focus. It's not that hard

Maybe you've been told this before, but here's what works for me without fail.

Put the image right up to your face, I'm talking like touching your nose. Then slowly pull away, really slowly. Don't move your eyes, keep them looking at and focusing however they are as you pull back. If you pull back too quickly, you can miss the moment it "pops". If you get more than a six or so inches away from the image and there hasn't been a pop, restart and adjust speed of pull back, it may take some fine tuning.

If this does work and you begin to see the layers "pop", don't get overly excited and try to look at the popped out part, because moving your focus or eyes too quickly will just drop the illusion. Keep pulling back at that steady speed until you have the full image in your field of view.

At this point, I usually can start looking around the image without losing it.

This is a little harder with screen, which is emitting light and can strain your eyes, but still works overall. Just tried it with this one after having not done one of these in years, and got it immediately.

Even if you know how to do them, this one is especially hard, because you only need to focus maybe 5% past the image. Basically, allow the image to split into two as you look farther into the distance, but not too far, or it won't work.

You dumb bastard! It's not a schooner... it's a sailboat!

I was having a hard time getting cross eyed stereograms to work, and stubbornly kept trying until after 2 or 3 months I finally succeeded. It was so neat I looked at thousands of images right away. That, however, has ruined my ability to learn how to see parallelview images, singe my eyes just default to crossed when I try to align the elements. I've not been quite as stubborn about it, but trying has also been a lot more frustrating.

It's a schooner!