Ask HN: What are some productivity hacks which junior devs should know?

Focus on iteration speed. Ship small changes as fast as possible. There’s no point trying to sit back and have deep strategic thoughts about what needs to be done until you’re so proficient at the basic mechanics of writing and deploying changes that it is instant and effortless. Just pick a clear, important improvement to be made to the system, find the tiniest change that makes progress toward that goal, do it and repeat as fast as possible. This should be your general modus operandi for a long time in your career.

A second point I would make, get yourself in a position (company/team/whatever) where you get exposed to lower abstraction levels. Mid/late game in your career it’s important to have an understanding of operating systems, databases, networking, memory layout, etc. Otherwise you plateau.