1) Interacting with a ton of people, especially in a public-facing professional context. While generally not great, retail and food service jobs are actually a good way to become charismatic. Especially at local cafes and shops where the veneer of ‘corporate-ness’ doesn’t exist.
2) Participate in some organized activities as a leader. Start a fundraiser, coach a local sports team, host a potluck dinner, that sort of thing. In many ways charisma and leadership are simply a matter of confidence, and the best way to build confidence is to put yourself in real leadership situations, even if the stakes are low.
I've noticed that martial arts schools often cultivate leadership. Once you've been training for a year or two, you will often be asked to demonstrate technique to beginners. Did wonders for my confidence as a teenager.
Similarly with the outdoors club at my university. Once participants had gone on a few trips, they were encouraged to plan, organize, and lead their own.
Any of a number of hobbies ought to offer similar opportunities.
There are loads of books and videos on it, "How to Win Friends and Influence People" is a classic. I am constantly getting youtube suggestions from "charisma on command", I occasionally watch them and they have some interesting snippets.
I think the most important thing there is to actually intact with people and practice these skills. I used to be quite introverted in my early 20s but then I got a job as rafting guide because I loved white water. Having to interact with new people every day gives you plenty of practice. These days I don't have a problem interacting with people. I probably am not top of the scale as far as charisma goes, but I am whole lot better than in my early 20s.
Look at people when you meet them and talk, shake their hand (not at the moment!), remember and repeat their name, tell them your name and something about yourself, ask and listen to them talk about themselves family/interests. Followup on the conversation if you want to keep them in your network.
Oh and you can practice this lots. Talk to people in the street, in shops, in bars. I think I improved this a bit going backpacking for instance as you have to communicate with lots of new people often without a common language
Warren Buffett was awkward and shy, incapable of public speaking, when he was younger. He points out that public speaking would make him physically ill. He credits a Dale Carnegie public speaking course [1], for breaking him out of that.
Today he can sit in front of a packed arena of 18,000 people and hold the annual Berkshire Hathaway meeting, while giving long speeches with the spotlight focused squarely on him.
A lot of charisma is about getting your personality out of the box it's being held in. Figuring out the strategy that best enables you to do that. Typically people don't lack for personality, they lack for being able to outlet it properly, understanding the method of doing that. It's like having a car in your garage and not understanding how to drive it; it's sitting there waiting and it'll take you places, if you learn how to drive it.
Charisma is the pairing of your personality with the system/approach of how you get that personality out into the world where it meets other people in a highly effective, impactful manner. You likely have a personality, you need the delivery system.
Buffett has a different type of charisma and a different manner of unleashing it, than eg Steve Jobs, Michael Jordan, Tom Cruise or Will Smith. Buffett's style lends itself more to a kind of folksy story telling approach, and it works extremely well for him and matches his personality strengths (for example he liberally uses self-deprecation to disarm his audience of their preconceived notions of elite wealthy types; he learned a very long time ago that people like hearing stories they can relate to and he channels through that mechanism often).
[1] https://www.cnbc.com/2019/03/21/billionaire-warren-buffett-s...
But I recommend therapy first, charisma will follow you working on your psyche
Therapy doesn't always have to be focused on very negative illness like depression or anxiety. It can help with positive sides of psychology. Maybe calling therapy a coaching session would be more appropriate in my post, but tbh it's almost the same thing