Success first and foremost depends on one’s goals, AKA, on what they’re trying to achieve. Whether someone succeeded is entirely dependent on what they were trying achieve successfully, and whether or not they have indeed done so.
You cannot succeed when there are no goals to be completed successfully, because success isn’t about being rich or being worldwide famous, but on your preferred attempt at accomplishing whatever you are trying to be accomplishing. Those, therefore, who are aimless in life, have nothing to succeed in, because in order to succeed, you need to have something to succeed IN; a purpose, a mission.
There isn’t really anything else beyond the importance of setting oneself one or more goals and attempt to reach them successfully, when it comes to the basic notion of success. Whatever else that is defined as “success”, it is defined so by the accordance of which society values in an individual orthodoxically.
Of course, there is this "objective" usage of the word "success," leading to the impression that there are indeed specific ways and specific things to be successful in, in order to be successful in the first place. Even if you are to succeed in things outside of this category, like video games, those would not count by many as "true" success.
Those include: wealth, high income, an active social, romantic, and sexual life, above-average material prosperity, a great amount of followers on social media, a luxurious car (maybe more than one car) -- basically anything that is either related to financial materialism, or greatly associated with whatever people find impressive that they find on TV and in gossip media.
However, your own goals don't have to correlate with those of society. Even if you endure the test of society's expectations, and reach the desired state of what they call "success," it is still not a success if reaching said goals are not your own goals. How can one become successful in completing a goal they don't want to be accomplished at, AKA, a goal that is non-existent in their own preferences?
Surely you "succeed" in them, but such success does not come from your own genuine desire; it comes from the norms. What success is there, therefore, in being a slave to external expectations, external dignity, in accordance to said expectations?
Some of us just learn to go with the flow and adopt the goals others impose on us. But as long as we don't really want to succeed in a goal that we don't want, we technically cannot succeed in it, even if we accomplished it. This is because the end-goal of success is to achieve a state of long-term satisfaction. And if you don't have that, then you're technically unsuccessful in your own terms, even if you are the opposite in the eyes of others.
How can someone be truly successful if they are not truly satisfied with their own work and achievements? Such success is pretentious; an attempt to please others so that you will not feel bad about not being normal and socially desired.
Therefore, one can define success in their life by whether or not they are satisfied with their current achievements, based on their individually-preferred goals.
If you are a wealthy businessman or woman but you despise your job, you are "successful" only on society's terms, which prefer to have citizenry that generates a lot of wealth. But again, if it's not your own goals, you cannot be satisfied, as the purpose of success, in the end, is the satisfaction of the individual or individuals who made it. Of course, having greater wealth is satisfying to many, but not many actually need that much money in order to have their needs and wants satisfied.