Reflect Every Single Day
As far as I'm concerned, the most valuable character traits that can be acquired - things like persistence, grit, integrity, and leadership - can't be easily taught from a book. Rather, they must be discovered through novel and challenging experiences. For me, I only learn from those experiences if I reflect on them and intentionally try to conceptualize and write down what I've learned. Reflection is the fuel that powers tacit learning.
Because I won't learn otherwise, my goal is to reflect on what I've learned, every single day. I will do this by making a few sentences of journaling in my Evernote workspace a daily practice.