What are some crucial aspects of web development (especially for production-ready products) that are often not mentioned in tutorials?

I am learning web development. I have done a few small projects, however, those are all in development stages which are far from ready for production.

My coding practices mostly come from online resources e.g. books, articles and tutorials. However, these are mostly for beginners. I love and appreciate all the tutorials but now I'm at a point that I want to look for more advanced and production-ready examples as well as coding practices.

Looking forward to hearing any suggestions. I'm focusing on Node.js so any recommended resources are highly appreciated.

Thanks in advance!