I learned Emacs by reading the Emacs manual[1], the Org mode manual[2] (Org mode was the main reason I switched to Emacs), the Emacs Wiki[3], and other people's config files[4][5].
Note that I didn't use other people's config files, such as the Emacs Starter Kit that another commenter referenced; I read them. I've previously used other people's config files, skeleton apps, etc. when attempting to learn new technologies, and I always ended up regretting it. With Emacs I started from scratch and took only what I needed from other people's setups. This worked very well for me.
I don't know if you have any interest in using Org mode, but I'd like to mention that using Org mode to create a personal wiki has been one of the best decisions I've ever made. I previously had hundreds of files (.txt, .doc, .xls, etc.) containing notes for the subjects I've studied, and these files weren't interlinked like wiki pages, nor could they be converted to HTML and published to the web with a single command. Sharing knowledge with my team and family is so efficient now. I can't recommend Org mode enough for notetaking.
[1] https://www.gnu.org/software/emacs/manual/
[2] http://orgmode.org/manual/
[3] http://www.emacswiki.org/
[4] http://www.emacswiki.org/emacs/CategoryDotEmacs
[5] https://github.com/search?type=Repositories&q=Emacs