How do you know what gift to get someone?

Usually I think about what they like and what problems they have going on. Like one person in my life commented on being cold a lot, likes cats, so I got her a nice blanket that has a giant cat on it. Not mind blowing or anything, but it shows I was listening. She loves it.

I tell people don't try to buy me anything technical. Like I've been thinking of getting a 4k monitor, but I'll do an excessive amount of research before buying one. If someone else got me one and it wasn't right for some reason, I'd feel terrible.