- Writing small, standalone, often throwaway programs to play with a new language feature, concept or API, or to answer a question about how something works or

- Writing small, standalone, often throwaway programs to play with a new language feature, concept or API, or to answer a question about how something works or performance. This helps with understanding but also got me over the fear of starting a new project from scratch. - Learning functional programming (and applying the above to that learning) made me a better programmer in the non functional languages that I still spend most of my time using. - Reading books and technical articles as an ongoing thing over many years, little bits of knowledge and understanding really accumulate over time. - I actually found that practicing coding interview style problems and using them as a motivator to better understand core computer science algorithms and data structures has improved my programming, I think for similar reasons as my first point above.