Hi everyone,
I'm Dan... looking forward to discussing my new book Algorithmic Thinking.
https://nostarch.com/algorithmic-thinking
What do you learn next after learning a programming language? Lots of answers

but IMO one good option is learning about data structures and algorithms (hash tables, recursion, dynamic programming, trees, graphs, etc.). Making code super efficient with data structures and algorithms never gets old for me, and I hope my book can help you if you want to learn this material. I've been teaching programming and algorithms for 12 years... I've tried my best to use everything I've learned about teaching this material. My overriding goal has been to make the book as approachable as possible, to break this stuff down and motivate people to jump in and not be intimidated. But you'll all be the judge of whether I've managed that.
I am also blind/visually impaired... and I had the funky experience of getting a print copy of my book last month and not being able to read it! lol. So I am also happy to talk about how I write, access technology, how programming works for me, etc. (And BTW, +1 to Coderanch for a website that just works for me.)
Thank you!
Dan