when i don't wanna be someones friend or associated with them... I don't look into their eyes when i talk or listen, opposite if i am. (Its very rare that I'm uninterested though)
If i am interested wanting to know them...i genuinely ask about themselves, and relate my own life into it...to make it a bit more personal.
(kinda like how i'm talking to you right now... like i'm genuinely interested in ur yt channel and the determination you have to get a 99.95..I would have ignored u and gone with my way if I wasnt).
It also depends on the other person's personality though. If their introverted, you've gotta do the talking.. I have this one friend who has a personality of like a stone. Some people may take it the wrong way and think she was rude. I make it my goal to make her laugh every once in a while, and occasionally she'd ask abt myself. Now when you make a person like her to talk to you, yk their genuinely interested