People who fall asleep instantly: How?

Exhaustion

You just gotta lay like this and

I keep my phone aside and close my eyes and think of unrealistic life situations and i doze off immediately

I have always been a pretty good sleeper anyway and most nights I don’t have any issues sleeping. But I have discovered in recent years that on nights when I am having trouble, I can actually force myself to sleep by basically ‘scrambling my thoughts’. It’s really hard to explain, but rather than thinking hard about one subject, if you just force your brain to jump from subject to subject quickly (the trick I use is using an image generated from one thought to generate a new unrelated one as fast as I can) it essentially forces my consciousness into shutdown and I go to sleep. As I said it’s a really tough thing to explain, but it works for me.

Easy!

I just try to stay awake, and fail.