I am passionate about self-development and ways to improve yourself. Up until now, I can say that I have mastered one critical aspect: continuous learning. Let me explain.
Business today requires us to always deliver great results, by providing decreasing resources to increase profit margin. Or, shortly put: MORE with LESS.
I don't think this is actually possible if we continue to do the things the same way we did it in the past - what worked then, might continue to work today as well, or not... So you have to be prepared to adjust to the new requirements, to change based on how the world around us change, always dapt and discover new ways of doing things.
My key learning was that I have to never stop learning, never stop reading about how others are doing things, how others achieve great results, and see how this might give me ideas on how to change. I might not apply it today, or not even tomorrow, but it does build a different way of thinking, it does open up your mind to new approaches.
I've found today one really interesting article from HBR called "How Companies Can Develop Critical Thinkers and Creative Leaders" - making a comparison of the experiential learning that happens in the army and the one that should take place inside companies, but does not. I suggest you reading it, and let me know how much of your time do you spend it in working at your job, and how much you devote to your learning (formal, informal, coaching, mentoring, reading, experiential)...