Welcome to the community forums!
The best way to start here is to ask and try to help into the forums (in my opinion).
As usual, you'll find information on StackExchange too and you can start diving into the http://devdocs.magento.com/ not only for learning but to correct and improve the docs.
Another recomendation could be to be aware of Magento issues on Github: https://github.com/magento/magento2/issues (if you are technical, of course).
Also, you should read this post: https://community.magento.com/t5/Welcome-to-the-Magento-Community/Start-here-and-hello-from-me/m-p/5... (in particular the guidelines)
So... as I said before, welcome to the community forums!