Personally I found that my productivity as a software developer was much higher when I was young and didn’t think so much about the cleanest code or the perfect architecture for a problem and instead just tried different approaches. Now I often feel paralyzed by having to “get it right” from the beginning.

Valid (in my opinion) lessons I cherish today are keeping individual parts of a code base simple and understandable, documenting and testing a lot and preferring simpler solutions over complex ones.