There are many different ways to define "success". To me, it boils to down to being able to make a living doing what I love, to the very best of my ability—which is to say, it's more about the journey than the destination. I don't (currently) have some grandiose goals of being a millionaire, driving a Lamborghini, and retiring to some tropical private island. Instead, I'm focused on doing what I love simply for the sake of exactly that: being able to spend a lifetime doing what I love and feel fulfilled by. Success is about personal fulfillment, not material things; money is only worth what you spend it on, so I only seek to have as much as I need to support the lifestyle I'd like to have.
Having said that, the question becomes:
How do I plan on creating and sustaining that kind of "successful" lifestyle?
Ultimately, it comes down to trading value for value—both in business and in my personal life.