I believe perseverance and grit are the most essential to learning. I also value the ability to stay focused and push through struggles despite the circumstances of success or adversity. I have had a lot of students reap success by maximizing the effort instead of the results.
I use the Japanese concept of kaizen. Kaizen refers to the idea of making small improvements over times on all different levels. It can mean tweaking aspects such as efficiency, harmony, and logistics by using a scientific method of trial and error.