Welcome to the community forums!
The best first step into the forums is to ask and try to help others.
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)
Fianlly, you'll need to get your hands dirty with the platform.