Here's how I (accidentally) learned to do it: hold up a forefinger from each hand, pointed at each other, with a very small gap in between. Now look at somethin

Here's how I (accidentally) learned to do it: hold up a forefinger from each hand, pointed at each other, with a very small gap in between. Now look at something in the distance through the gap: you should see a magic "hot dog finger" floating in the air between them. Once you can see this, alternate between looking at your fingers and looking at the distance. Once you've got the mechanic down, you can start intentionally unfocusing without anything in the distance to look at, which is what it takes to see a magic eye.