Go out of your way to talk to people. Smile at them, learn their name and make sure they know you remember it. Learn the art of nonvapid small talk.
It takes an minimal amount of effort to learn two or three small things about someone, and you will never in your adult life have too many friends or business contacts.
You don't have to persuade others. Let them be. Just do your own thing.
Forced work doesn't have forced result. It just doesn't work.
Let things happen naturally in your life: water finds its own level. Not have a girlfriend? Probably because you don't see enough people daily. If you keep working on what you love, you'll meet people with the same taste, and you'll click with them way more than you would, if you wanted to force yourself to have a girlfriend (who doesn't care about what you do anyway).
Admittedly, in some jobs you don't see enough girls and women around (remember all those jokes about programmers?), while in some other jobs like dancing, theatre, music, etc. you'll see many. This improves your chance of having a great relationship with (mostly) more beautiful girls. Now I'm not saying you should quit being a programmer and become a guitarist to attract girls, just know that at the end of the day, you can't have best of both worlds.
Basically that any advice you receive is going to be just plain wrong.
Turns out it's true! People extrapolate advice out of their own unique circumstances, base advice off nonsense they see on the news, or just make things up to sound smart, just to name a few problems with most advice.
Think honestly and critically about the next piece of advice you give/receive.
It takes an minimal amount of effort to learn two or three small things about someone, and you will never in your adult life have too many friends or business contacts.