Your best bet is Emacs itself.
When you start it, a splash screen appears (if not, press Ctrl-H and then A). There you will have a chance to run the Emacs tutorial. It gets you at running speed so you can move around and do some editing to a reasonable extent.
What comes next varies based on your requirements. I remember starting by editing my source files in vanilla Emacs, and when something became too tedious, I Googled it, and installed a bunch of packages (I have 160+ packages installed right now).
For ideas and Emacs news, you can visit Planet Emacsen, a federation site of Emacs blogs. Emacs SE is a StackExchange site for Emacs Q&A. Last but not least Hashnode has an Emacs node, too; feel free to ask away!