If you don't quite have the knack for relaxing your eyes to see these, here's "one weird trick".
Position yourself with something behind you (such as a window) that you can see reflected on the screen. Focus on the reflection so you are looking "through" the screen. Now re-focus on the screen, but not immediately! Hold your focus and let it "slip" as slowly as possible. At some point your eyes will converge at the right depth and you'll catch a glimpse of the shapes behind the screen. When you see the pattern starting to come into focus, lock your eyes onto it. The first few times you'll probably catch a glimpse but fail to lock on. Repeat until you get the hang of it.
Nope. Doesn't work. Everyone's advice fails to work for me. I tend to think this is just a mass conspiracy or giant elaborate joke. I'm going to use this JS script to generate tests to see if I can get people who can do this to tell what the number is behind this "magic eye". Call everyone on their bullshit.
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.
A small number of people will never be able to see them, but AFAIK if you have normal stereo vision (no lazy eyes etc.) then you should be able, with practise. Since these particular stereograms use coloured random dots, the colourblind might have some extra trouble with them.
I messed around with SIRDS quite a lot in the 90s. I found it hard to see them at first, but the reflection technique initially worked for me and after a while, I had no problem seeing them and even started seeing them by accident in wallpaper patterns and the like.
Another thing that makes a difference is the width of the strips used in the stereogram compared to your IPD. Depending on the width of these, it might be easier to sit closer to, or further away from the screen. Once you get the basic technique you can tolerate a wider range of widths, but at first it can be tricky. It might help to start really close to the screen and slowly move your head backwards as you try to focus.
If you cross your eyes, can you get a reverse (inset, concave) image? I don't understand why magic eyes are always implemented in the way that requires people to do something almost impossible (ignore an object in front of them and try to focus on something further away) when almost everyone can cross their eyes and those that can't can probably force their eyes to do it with a piece of string or a pencil or something. I still have never managed to see a magic eye correctly (outset, convex), but can at least decode what other people are seeing in reverse by crossing my eyes :(.
I bounce my eyes in and out of this many times a day. Whenever I see two like things next to each other i'll line them up. Eyes, light switches, books. I've been able to do this at will since I was a young child.
never in my life i managed to see this things. even back then when they were in fashion. no matter how hard i tried. I'm starting to get worried something is wrong with me.
Position yourself with something behind you (such as a window) that you can see reflected on the screen. Focus on the reflection so you are looking "through" the screen. Now re-focus on the screen, but not immediately! Hold your focus and let it "slip" as slowly as possible. At some point your eyes will converge at the right depth and you'll catch a glimpse of the shapes behind the screen. When you see the pattern starting to come into focus, lock your eyes onto it. The first few times you'll probably catch a glimpse but fail to lock on. Repeat until you get the hang of it.