Studying open-source code brings immediate benefits to your own code.
factore.ca
factore.ca
Check out Dr. Spinellis' Code Reading:
"Code reading requires its own set of skills, and the ability to determine which technique to use when is crucial. In this indispensable book, Diomidis Spinellis uses more than 600 real-world examples to show you how to identify good (and bad) code: how to read it, what to look for, and how to use this knowledge to improve your own code.
Fact: If you make a habit of reading good code, you will write better code yourself."
With one _giant_ exception: there are too many bad code out there so be very careful.
People often do one but forget the other.
Skillful programming requires a weird mix of both attitudes.