The "fake it till you make it" concept absolutely works, and becoming even slightly confident encourages you to make fun of yourself, or put yourself into uncomfortable situations, which eventually further builds confidence-- it's a self-validating feedback loop in the most healthy way possible. Once you get to the point of calm, comfortable confidence, your "game" becomes the easiest thing ever. You just make people feel good about themselves, and the response is overwhelmingly positive. Strangers will see you talking with other strangers, and will chime in just to join the conversation. I've been making an effort for perhaps 8 years now, and there is no finish line, but that's the fun of it. I make endless mistakes (and I'll make plenty more tomorrow), here's what stuck over the years:

  • Make fun of yourself. It can never be delivered in a way that begs for an "awwww no that's not true :(" response. If someone in the group pokes fun at you, take it entirely to the next level of embarrassment (literally and sincerely laughing as you deliver a joke against yourself). You can cross pretty much any line in humor, when you make yourself the subject of the punchline. People laugh whether its funny or not, just because you're throwing yourself under the bus. That's why it's so fun to respond to a jab at you. You can take it to any level of utter embarrassment and it will be received well, when delivered with confidence. Respond to a jab with "Oh... oh no it's far, far worse than that, this is what it's TRULY like: blah blah".

  • Don't hesitate to ask somewhat more personal questions with people you've just met. When someone is telling you about their job, and you can tell they seem to enjoy it, be honest and say "hey you seem really passionate about your career, I see the opposite far too often, what exactly gets you excited about it?" or playfully challenging someone to back up their response with a story or evidence. I've had overwhelmingly good responses with asking more intense questions within the first 60 seconds of meeting someone (without crossing any common sense boundaries of course), and it has validated my optimism that most people want to "cut the crap" too and have a meaningful conversation with someone, even a total stranger that shares their brainwave at the moment.

  • Compliment sincerely and with complexity. I learned this from the actions of my first boss. When you compliment someone, speak deliberately and slowly, and back up your compliment with a piece of evidence or description. It works the same as the advice on complimenting for example the style or clothing of a girl, versus a physical feature of hers. People love to hear that the effort they put in is impressive. Just like the effort of running releases endorphins, the effort anyone puts into their appearance or demeanor is immediately validated in their brain through a sincere, specific compliment. It makes them think "I tried hard and put in effort today, and it totally was worth it", and every human shares the satisfaction of a worthwhile effort, it makes you feel ambitious. Look back to "parent compliments" (the ones your parents might give), and how little impact they have on you. "You're doing awesome!" from your mom/dad is met in your head with "pff they're just saying that because they're my parents" is a natural response to a vague compliment that has no evidence.

  • If you're introverted or reserved (or not, even), verbalize your thought process in a positive way. If a girl tells you something that is legitimately impressive, and in your head you think "that's impressive", say it out loud too. Look her straight in the eye (touch her forearm or shoulder too if that's your schtick) and take over the conversation for just a moment: "Hey. That's actually really impressive." Don't break eye contact until she responds, which happens quick anyways. This works especially well with a mature confident girl, and the best response is this, which takes place in one second or less: [pause. blink. stare at you. beam. "Thank You!". blush. look down. forget where she left off. still looking down because she's hiding a smile, and saying "um yeah! so so um"] This took me YEARS to understand. I would have endless compliments in my mind about people (guys/girls, doesn't matter), that I would never consider actually telling them, even though it crossed my mind all the time. Think about when you were randomly complimented last, about anything. Your chest puffs out and you feel GREAT for the day. You admire that person for making your day so enjoyable. It's so dang easy to help lift a persons day up, and all it takes is verbalizing what you already believe.

  • Use people's names repeatedly. When 90% of people answer the phone when their friend is calling, they say "Hello?". This is an odd social relic from a time when you truly didn't know who you were speaking with when you picked up the phone. Every phone has caller ID these days, you know exactly who is calling, why do we pretend we're hearing a disembodied voice while lost in a cave? Answering the phone with a (literal) smile and "[Name], how's it going man?" is always met with a warm, excited response. Think about when you call someone up and they answer with "Hello?". You FEEL the need to explain yourself, as if you are invading their time. If someone pleasantly answers as if they had been waiting for your call this whole time, you feel validated and excited to continue talking. This is especially true with answering the phone with a date calling for the first time etc. Try answering with a slow, deliberate "heyyyy [her name], what's up?" with a smile. It's always met with a "Hey! Umm not much, I was calling because...". So much better than "Hello?" "...Oh hey it's [name]..." "Oh hey... how's it going?". The same conversation occurred, but it started off one step too late for no reason and the pace is tripped up now (because of that damned awkward question "who is this" when you already know!).

  • Realize that life is pretty much the most elaborate cartoon strip ever written. Your asshole boss that chews you out? He's just a cartoon character in your cartoon, and even though you don't want to admit it, you getting chewed out is actually pretty hilarious. We watch Seinfeld and are in stitches about how shitty George Costanza's life is. He is a bumbling fool that gets himself into awkward situations constantly. When you have a terrible day, and zoom out and become a third person viewer of your own life, as if it were a sitcom, it actually becomes pretty hilarious really. Just how perfectly terrible your day went, the odds of it, is really pretty funny in a way.

  • If you're complimented, smile and say "thank you" or "thank you, that means a lot to me" if you mean it, and make genuine eye contact either way. When you compliment a girl, the best outcome you could hope for is her blushing and saying "thank you" with a smile. It's validating that you made somebody feel good.

  • Don't know what to do with your hands while talking? Get comfortable with hand gestures while explaining something. Having a girl's eye contact bounce back and forth between your hands and your face is a great thing, it means she's intrigued. One of the most flattering compliments I have received from a girl was an off-the-cuff "wait, can I just say you have the best hand gestures when you're explaining something you really care about". Speaking of, that girl NAILED a good compliment, it was completely unexpected and unconventional, it made my day.

  • Poke fun in a light hearted, playful way, but compliment deeply and sincerely, and do them both frequently. Having a girl burst out laughing and say "you're such an ass" when you tease her, and then blushing later when you tell them something you admire about them maintains playfulness, challenge, and excitement, but also validation and flattery. Everybody enjoys being flattered sincerely by someone they respect.

  • For some reason, when first responding to someone's question where you have a passionate response, starting with "OH man [their name],..." either in a text or face-to-face conversation lights up the face of the person asking the question. In the same vein as verbalizing sincere, internalized compliments, acknowledging someone's question as "thoughtful" (when it truly is), is incredibly validating. If you're the person asking the question, you feel like you just struck a chord with that individual. "OH man Heather, I love this stuff so much I'll never shut up about it, you'll have to do the honors for me blah blah blah".

  • Life is funny, I've already mentioned it. Interacting with random people is entertaining for that reason: If you both witness some crazy situation (like a homeless guy fighting a tree or something), make a comment to them, they're likely thinking the exact same thing and have no friends around to verbalize how absurd that situation was even though they're dying to. If you're out in a social situation (music festival, beer walks, places where random people start conversations with you), and somebody opens you (guy/girl, doesn't matter) with a random observation, don't respond with "heh... yeah for sure...". If a random person starts talking to me, I start smiling ear-to-ear with the thought "oh man what's this guy got to say", and a person witnessing an instant smile responds favorably, they've been validated and they relax. To top it off, you respond instead with "GOOD GOD YES! It's exactly like that! blah blah blah", and you will see the person re-adjust their posture, they will spring up with energy, even turn so that you're both standing side-by-side and facing the crowd together, it's you and them/her vs. the world at that point, and that's a great place to be.