I am sorry, but I don't know any resources... I have collected a few things on the following page: http://users-cs.au.dk/rav/vim/

Basically, I achieved my wizard-level C++, Vim and Git knowledge during my three years as a part-time student programmer in the basic research center MADALGO. I took the time to study the documentation (respectively the C++11 draft, :help and the git man pages) whenever I was curious. For Vim in particular, I made sure to eliminate all repeated keysmashing in my daily workflow, which "unfortunately" required me to learn about macro wizardry.

My only advice is to keep practicing, to keep trying to spot inefficiencies in your own workflows, and to actively eliminate these inefficiencies by studying the Vim help pages.

Over the years, I've got a lot of mileage out of "Learning the vi and vim Editors" from O'Reilly, and web pages like http://www.lagmonster.org/docs/vi.html. Practicing and testing compositions based on what you learn from these will go a _long_ way. Try new ways to move (by screens, by sentences, by blocks), test using your buffers, experiment w/ transforms. Then, one day, you realize you're pretty good with vi.

I like http://learnvimscriptthehardway.stevelosh.com/ , which covers a different set of features.