Time. No matter what you do, putting in the hours of practice gives you the experience and exposure needed to get better. Whether it's art, music, tech, cooking, language, or whatever, there's truly no substitute for spending time.

Beyond that I think it's good to use a broad approach where you switch between variety of things like naive exploration, studying masters, theory education, etc. (It's no good to just study music theory, for example, you need to also be learning existing songs and playing around with your instrument in an intuitive way. I think the same concept can be applied to many other skills )