Learn Vimscript the Hard Way - http://learnvimscriptthehardway.stevelosh.com/
Vim is incredibly powerful out of the box, but it doesn't truly shine until you take some time to customize it for your particular work, habits, and fingers. This book will introduce you to Vimscript, the main programming language used to customize Vim. You'll be able to mold Vim around your own personal text editing and make the rest of your time in Vim more efficient. ‎- Скажи это моей лошади