Most people believe that success is an end-state - being fit, being rich, being famous, etc. You "achieve" or "reach" success.
Truth is, success is a skill, which means it's something you have to learn how to do. It is a process, not an end-goal.
Large successes are built upon smaller successes. A successful person is not someone who simply reached a certain state, but who kept and keeps on building on smaller and smaller successes.
For example, becoming a successful writer means that you learn how the writing world works. Maybe you start small, with short stories or articles for a local magazine. You learn how to sell yourself and your work, build a readership. Then you move to a bigger publisher that pays better, and so on.
If success is a skill, then that means it's learnable. You can break down its essential sub-skills, practice them, develop them, and make progress towards mastery.
It also means that the process is more important than the end-product. No one learns a skill just so they can discard it and never use it again.