Accepting it. Looking in the mirror hard and saying "this is who I am." Thinking long and hard about what you cannot change, but what you can change and haven't changed. Learn to accept life isn't fair or just.
Some son of a bitches will be born into a millionaire family, get to do whatever they want - fuck anyone they want, go anywhere they want, eat whatever they want, commit any crime they want - and get away with it with no consequences. That isn't fair or just. But that's life.
However, there are things which you know are making you miserable which you can change. Change that. In fact, change every "that" insofar as you are able to.
Upset that you don't have a clean face or body? Clean your face and get in shape. Join an oil painting club. Join a drawing club. Join a fencing club. Find a martial art. Join a bowling club. Something that you genuinely want to learn and do.
Upset you didn't learn a skill or hobby? Find a skill or hobby you like, excel at it.
Upset you haven't been moving up the corporate ladder? Work twice as hard.
Upset you don't have friends? Make efforts. Join communities; churches, hobbies, work, etc. Maybe find a community online where people aren't afraid to be non-anonymous, and meet up with them at some point. Face your fear of rejection and ask someone to get a drink.
Upset you aren't educated? Find some lectures online. Online classes. Learn about the world / a skill. Get your GED if you don't have it. Maybe get a community college degree if you don't have one.
Be happy you changed that as far as you know you were able to. Be happy that you can take pride in that you chose to face yourself and overcome yourself. Then die peacefully of old age.
Again, almost every religion in the world - Hinduism, Christianity, Buddhism - says it's a fools game to try to find justice in this world. One Saint in Christianity once said "I would go insane if I saw the world and knew there was no God afterwards." That should tell you that our illusions of "justice" are just that - illusions. Human beings are too selfish for pure justice to be achieved.
I don't see any other solution besides being sorry for yourself, suicide, or escapism. And escapism only gets you so far, you have to face this life at some point.