Initiative, feel the vibes for compatibility, try to find out subtly if he/she has good friends that might be interesting and do the same thing for him/her.

People are awkward, they all feel nervous to a certain degree. Be forgiving with yourself and others, but don't bite more than you can chew.

Really it's about saying to hell with privacy and not thinking about intruding in other ppl lives: most of the time they actually like it if it was a cool interaction at least!

If you really are nervous, try starting with saying randomly hi to strangers that aren't in a hurry maybe add a platitude, ask the time by "accidentally" forgetting your phone, bum a cigarette off the cool guy, comment on the weather for old people. Give a compliment! Enjoy living, and don't mind if you ever get a bad interaction, sometimes you randomly encounter someone at their lowest point or at their worst because of a personal problem, hangryness, or they just talk rudely by habit.

And if you want to meet specific people with specific interest: where do they hang out? Online? Offline? Then you proceed with a friendly hello or smile.

Develop a hobby and interact with others in it

We may be autistic