Pick and learn a single programming language properly (like I am doing with golang)
Write unit tests and CI (Ah, now it makes sense)
I have not written serious tests in my 1 year long career, rest apart from the 4 year tech journey. Now it makes sense, there is a purpose to give me confidence to build reliable software.
Make refactoring a habbit (encourage to do, but done or not is sometimes not in our hands especially for juniors)
Pair with people (I do frequently whenever the need arise, and learn a few git commands and browser speed up shortcuts which help me learn more)
Read books (I am currently reading Learning SQL to learn SQL in depth)
Teach what you learn (doing it by youtube or articles I post)