If you look at professional sports leagues, you will see teams that win. Those teams will get more money than others, which they will use to improve themselves even further and try to win again on the next season. On the other hand there's the other teams who don't win a lot, therefore don't have access to major improvement and have it almost impossible to be competitive with the big guns. The art business is very similar - successful artists are successful because something they did was successful, which went much like a snowball - while starving artists on the other hand, almost always die starving and unknown. The same way, it works in any competitive system where someone has to win and someone else has to lose. These are examples of feedback loops.

Since we are basically monkeys competing for power, we can also see social/sexual performance as a feedback loop. Let's not label things "alpha", "beta", epsilon or whatever for now. A man who is useful, socially skilled, attractive, busy, serves a purpose, and in short, improves and creates survival possibilities for the species will naturally obtain a fair reward thanks to the sole nature of the system he is a part of, which will boost his motivation to go and do more of it. This is a positive feedback loop. On the other end of the spectrum, we have someone who doesn't get taken too seriously by peers or sexual partners. This person just sort of, exists. Does what he do for money in order to survive and goes home to play online games, or does whatever with his only 2 or 3 friends who also aren't particularly desirable. He might have it accepted or not, but the only truth is that he does have a reputation for loser. This person is, instead, trapped in a negative feedback loop, and judging by the fact you clicked on the title, you are probably in the need to get out of this loop too so let's get to it.

Reverting a negative momentum is tough, you are not just back to square zero but back to square -10. Being known as the loner, the loser, the beta, the insecure or the weirdo is an extremely damaging reputation, because translated to monkey language, it means: "THIS GUY ISN'T DESIRABLE AT ALL, DOESNT CONTRIBUTE TO OUR SPECIES AND DOESNT DESERVE TO BE TAKEN SERIOUSLY". Indeed you don't deserve it, because you did all the right steps to become the whole opposite of successful on the big scheme. People aren't wrong, you are wrong. If you are the complex, misunderstood, overthinking type, you'll have to dumb down to monkey thinking to understand why people like what they like and behave the way they behave.

It really comes down to one simple tactic movement: disappear from wherever you are, appear somewhere else and start from scratch.

First thing you'll want to do is leave it all behind (ALL of it), set a day zero and don't just "feel" like a new person while acting out an image, as people will see through this - instead, actually BE what you want to be. Embrace it from within and get into your character all the way through. Don't go for the "now I'm the absolute alpha" archetype because it truly isn't credible and doesn't work, but a regular bloke who gets what he wants out of life, barely cares about the others, doesn't worry/panic/hurry or give two craps about anything, and really have it all together. Lots of goals, lots of projects, basically being a new product getting a lot of hype - an asset. Almost like the stock market - you are valuable because people believe in you as an investment right now. Just make sure you don't talk a lot about all the cool stuff you do, let people find out.

You'll have to establish within a completely new social group and be successful within the group

At some point someone will be curious about your past and how you came up from nowhere, why you don't already have a lot of friends and so on. You will be asked if not questioned about this, and dealing with this is what will make you strong. It took me two failed attempts with different new groups - what worked for me was a combination of a "mysterious" character, shit test skills and a very well thought out story where all ends meet which I keep straight up to this date. Make up your entire life if it's necessary, just do it well.

To finish up, this is something nowadays we don't get to hear too often in an explicit, autistic-proof way; but then get to find out when it's too late: SEX MATTERS. Nobody believes you don't care a lot about sex, nobody believes you don't want to fuck a lot and nobody believes you get laid if you don't prove it. You want to fuck and you know it. How much sex you get, how many partners, what quality of partners. First thing people check is your position in the sexual market - if you aren't seen with women too often, NOBODY will think you are "reserved" in that department and you smash a lot in your private life - you are just beta in their eyes. Don't be that guy. Get out, flirt, be seen playing the game, this will be a fundamental pillar of your rise.

Being socially useful (as well as sexually competitive) gives a whole new outlook on things which you can't resign once you experience it. A man who is contributing to the survival and improvement of the species, that's all you have to be.

edit 1 (sep 7): I know it's long and drastic, but this is typed out in the exact way I would have wanted to see it when I was dealing with this, and it's aimed to what is known here as "autistic" types, who have earned a negative reputation across a vast area. you can repeat BAD AUTISTIC!!!! all you want, but it won't help people in that situation.