Henry Stanley wrote a blog post “Becoming a dramatically better programmer“. He outlines areas where programmers who want to get better can focus on. That is learning skills directly on the one side and learning meta-skills on the other side. Meta-skills: learn about “deliberate practice” – do things that challenge you and get feedback -, identify common mistakes you make and learn to do deep work – focus on work with no distractions.
My advice for deliberate practice are sites like CodeWars where you can solve exercises (“katas”) in a couple of programming languages. It is challenging (CodeWars has martial art like grades of mastery) and you get feedback by being able to look at solution by other users and thus being able to compare them to your solution.