Read other peoples code. Pick something open source that is decent and read it like you are critiquing it. You’ll see techniques you’ve not contemplated. You’ll see concepts you simply weren’t aware of.

My first mind blown code read was TeX when I had to compile it off a tape to get it to run on a Pyramid in the late eighties. I learned so much it felt incredible. I’m sure there are much better code based now. Perhaps the source code for Git.