Comment by ruszki

Fail, and try to understand why. Don't be quick with the answer. Sometimes it takes years. But it's crucial to want to improve, and recognize when the answer is in front of you.

Read why programming languages have the structures what they have. Challenge them. They are full with mistakes. One infamous example is the "final" keyword in Java. Or for example, Python's list comprehension. There are better solutions to these. Be annoyed by them, and search for solutions. Read also about why these mistakes were made. Figure out your own version which doesn't have any of the known mistakes and problems.

The same with "principles" or rule of thumbs. Read about the reasons, and break them when the reasons cannot be applied.

And use a ton of programming languages and frameworks. And not just Hello World levels, but really dig deep them for months. Reach their limits, and ask the question, why those limits are there. As you encounter more and more, you will be able to reach those limits quicker and quicker.

One very good language for this, I think, is TypeScript. Compared to most other languages its type inference is magic. Ask why. The good thing of it is that its documentation contains why other languages cannot do the same. Its inference routinely breaks with edge cases, and they are well documented.

Also Effective C++ and Effective Modern C++ were my eye openers more than a decade ago for me. I can recommend them for these purposes. They definitely helped me to loose my "junior" flavor. They explain quite well the reasons as far as I remember.