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.
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.