Programming

Learning by doing! Personally the best learning experience I had, was going to the roguelikedev subreddit, picking a tutorial in the language of my choice and diving right in.

This has many benefits: It's beginner friendly since pretty much all of these tutorials start from scratch and have a gentle learning curve so you don't need any prior experience. Because you're creating a game, you can just have fun exploring all kinds of nonsense.

This will keep you engaged and learning programming/languages comes naturally as you're looking to find ways for implementing whatever you want to try out in the game. Game development inherently touches a lot of different concepts, so you'll be learning many different facets of the language.

After the tutorial is done you can keep developing your game and continue growing with it. Or, if long-term commitments are not your thing, throw it away and start a new better game, applying all the lessons learned, right from the start this time. It's all up to you.

For me, personally, working on an actual project is much more conducive to picking up all the little details of software development, rather than doing small disjointed leet code exercises.