Eduardo Briceno realised that he is not getting better at things that he cares about. Even though he was working hard on them. This stagnation is actually common. He learned that the most effective people alternate between two zones, the learning zone and the performance zone.
In the learning zone they concentrate on the things they haven’t mastered yet, they try to improve and most likely make mistakes and fail. In the performance zone they concentrate on the things they already have mastered, they execute something with as little mistakes as possible. Here is his great TED talk.
This reminded me of an episode of Abstrakt, where Christoph Niemann talked about his Sunday sketches. He takes time every week to do whatever he likes, with no specific goal, and often comes up with great ideas. When under pressure of a deadline, there is never time to experiment and do something risky, you do what you know works well.
We are most of the time in the performance zone, when working, but also in private life. To make progress in a skill and to be creative, we need to change into the learning zone regularly, experiment and make mistakes.