You have potential: all the things you could do, the person you could be, the things you could have.
Then there's reality: what actually is right now for you.
There's probably a gap between the two.
Success is simply the act of working to close this gap. Not actually closing it, as goals may change and some you may not ever reach, but taking constant action to get closer to it. If you can do that, you can be successful.
If you are doing that, you are successful.