Are you familiar with Spacemacs? As a Vim user, you can be productive on day one because it lets you emulate Vim (via Evil). Spacemacs also comes with batteries included and makes it easy to move past editor configuration to whatever you're trying to get done. If you want more customization, Spacemacs is still Emacs, and can be extended as you wish.<p><a href="http://spacemacs.org/" rel="nofollow">http://spacemacs.org/</a>
Here's how I learned it. I downloaded it, installed it, ran it. Then ran the built-in tutorial and worked my way through it slowly. I then started using it for every day editing. I then created my own cheat sheet (in Emacs) based on commands I needed immediately. As I needed to do more things I extended the cheat sheet. I worked through online tutorials and read Stack overflow to figure out how to build out my .emacs file with the options I needed. Been using for more than ten years now and still learning!
If you're just starting, the Emacs tutorial is available from the front page, or C-h t (Control-h then t). Worth doing a few times.<p>Sacha Chua has some great cheatsheets (<a href="http://sachachua.com/blog/category/geek/emacs/" rel="nofollow">http://sachachua.com/blog/category/geek/emacs/</a>), including basic ones on orgmode.
In addition to tutorials, use it for real, but starting with some fairly trivial (in terms of complexity) tasks - like editing .config files. Then add more complex tasks - perhaps editing LaTeX files (this is actually how I started on Emacs - AUCTeX, the Emacs package for TeX - is surely the best LaTeX editor).
Use it. Do one tutorial to teach you the basics (navigating within/between buffers, opening files, tiling windows...) and then just use it. The first week is going to be a pain, the second and third tedious, after that you'll be cruising ;-)