The accumulation of little bits, particularly with regard to Van Gogh, generates something other than the sum of its parts. With regard to the paintbrush, a mass made of just bristle and bristle and bristle (for instance).

It's not the sudden ambitions you take on that will have significance. It's the small things over time. Small habits, small considerations, small things made, and even small listenings. It's taken years of watching and listening to others for me to confidently price my time and my worth. It took decades of scrawling and erasing to generate a novel, and not just a novel, but an ease in writing new things. 

The key is not just to develop new things, it's also to develop abilities. This is, in fact, where I have a challenge: when a sustained effort over time does not develop ability AND new content, I get discouraged. The modern sensibility would have us believe that learning to do anything (like how to apply for college or how to do your laundry) is useful, and has universal, applicable lessons, but you have to dig to get them. A lot of lessons are disposable. You learn them quick, they serve their purpose and then there's no point in studying the matter further. Submissions, for instance, discourage me in this way. You learn to do them and then you just keep sending. You can only learn how to take rejection once. Once the lesson is learned, nothing new is gained except more chances and finding a good fit for your work. No skills are sharpened, few new challenges arrive. You just keep sending. 

So if you find something that is sustainable, that is small bits over time, that can help you make things AND develop your skills, keep doing it!