And I was really bad. Nowadays I don’t have a chance.

I mean, you might just not be good at it, and this is like asking how to be 7 feet tall so you can play in the NBA.

That's how variation works, there's likely other aspects you're good at and others aren't.

Like I said in another comment tho, it's not like you can learn what to look for, because the things you're conciously looking for are the same things the people making it are aware of.

The only way to come close to "learning" is to just look at a shit ton of AI pictures while reminding yourself over and over "this is AI". Like, for a while, maybe 30-60 minutes at a time. Do the same thing for real pictures but repeating "this is real" as an internal monologue.

You're just hammering a label unto your various subconscious processes until they start shoving everything into that binary label system. Either "ai" or "real".

But again, human variation. There's other reasons to jog than beating Usain Bolts 100m dash time, you might not ever be great at it, you might not even see much improvement.

But doing that enough would eventually make you better at picking up all the little signs that others are noticing. It's exploiting how our minds work and want to see patterns.