We Don't know. Ask failure

success is to still be alive.
success is to not be in jail or prison
...to be able to partake in the hobby

it's having enough time, energy and money to play #1.  It's being happy by minding my own business on things that don't concern me.  It's making sure there is a balance of making sure those that I love, have their human needs met without compromising time for myself.  It's eliminating, or at least minimizing energy vampires from my life.  It's being a great forgiver and getting up, and moving on when someone knocks the breathe out of me.  It's having the courage to repeat the same opportunities that I have previously failed.  It's being who I am, with my head held high, mistakes and all; and giving others the permission to be who they are.  I don't have to be around those I find intolerable, unkind, and not peaceful. and dangerous to me physically, emotionally or spiritually.

for me, it is a matter of how truly happy you are.

I don't think that there's very many people who seriously sit down and decide at age 18 that what they want to do with their life is be filthy rich. When you ask little kids what they want to be when they grow up, they say stuff like, "I wanna be a doctor" or a "fireman" or "President" or "a policeman".

No one ever says, "I want to work in a factory". They never say, "I want to mine coal". They never say, "I want to be the CEO of a Fortune 500 company".

A little proverb I once heard: "It's rational for a butterfly to walk, but only if it don't have wings".

Suppose you're a research assistant working in some lab and you just came up with a cure for dengue fever. Are you successful? Somehow I don't think you'll be on Bloomberg TV getting professionally rim jobbed by Bloomberg's paid sycophants.

Maybe we ought to ask if success is a good thing. If your job is owning an aluminum manufacturing plant that pumps out millions of pounds of mercury into the atmosphere, and you're getting rich doing it, should you be called "successful" or a serial killer?

It's too bad that capitalists never have to do what doctors do and take the hippocratic oath. The moment capitalists have to promise not to do any harm, the entire system falls flat on it's face.

So remember what "success" really means. Or rather, how the meaning of that word has changed due to capitalist propaganda. Success means being really good at stealing other people's labor, wealth, and money and claiming you earned it. It means you're a really efficient high-tech purse snatcher. We might as well call half the US prison population "successful" by that metric.

When someone can figure out a way for them to not have to spend nearly every waking hour working and still survive, then that is success. When someone can do well for him or herself, while making the world a better place for others, then that is success. If you can leave this world a better place for your children then what you were born into, then that is success. If you can figure out a way to cure a disease, or eliminate a painful and costly problem, without harming others, then that is success. Rich people bragging about the size of their bank accounts is not success. No more than a heroin addict bragging about all the car stereos he's pawned.

For me any ways.  

To be happy in one's life, it takes,  

Education
Health
Money
Family
Self Worth
Confidence in one self
Make mistakes and learn from it
Gaining Knowledge all through life

We are all born with varying degrees of intelligence, attractiveness, mental and emotional stamina and resiliency. If a person uses each to it's full potential, to me, that is success, except if s/he use it for illegal means.