A few thoughts...
in reply to Learning the Deeper Secrets of Perl
Reading and studying only helps to a point. I find fixing, adapting, and building things is a better way for me to expand skills. This improves both developer skills and Perl skills.
Developer skills involve computer science, work habits, planning techniques, and more. Much of this is learned more easily from others than from books.
Perl skills tend to involve specific tasks like file processing, hash manipulation, and data base interation. I find that even when one thinks they know a language well, there tends to always be something else to learn.