Anyone is welcome to contribute to the project. The add-ons will enhance the use of CDX and provide more game like tools. Third, if you really want to be on the cutting edge of development, you can join the CDX Maintenance team and become a regular maintainer of the library. Maintainers go in and fix problems with the library, add new features and generally keep CDX running smoothly. Anyone is free to join the maintenance team.
Information is posted on the website about how.
Well I'm currently writing a book based on CDX and game programming. As for coding, I can't emphasize enough to always do it. Just sit down whenever you have a chance and code. Start a small project if you have to. Just to keep your skills up and increase your knowledge and awareness.