Are there specific publications or tools that you use to keep your knowledge and skills up to date?
I read. I read a lot. Articles, comments on said articles, papers, publications, books, reviews of said books, code, comments on code, etc. Reading is not the only requirement for mastery, but it is a prerequisite and the precursor.
After reading of course, there is a equally important secondary step: thinking critically about what you have read. This is a blend of looking at cross references and performing your own analysis and verification. Without this, you have no way of curating sound, logical content from misinformed nonsense. Sometimes, something that really *seems* right, is actually wrong, and understanding the difference is necessary if you want to be a trend setter and not merely a trend follower.
The crucial element is to put what you learn into practice. There isn't really a substitute, as this is where you validate your analysis in the second step. Without doing this, you would never know if you were right (in which case your confidence is reaffirmed), or wrong (in which case you can course correct your thinking).
Lather, rinse, and repeat. Always :).