A friend and I have started an online language learning school with quite an unorthodox name : ) and a totally amazing way of learning. Getting thoroughly pickled in the language - the only surefire way to know it.
At the beginning of 2018 we are running a free 14-day winter course for learning English - if you can find a spark of the holiday magic in you, please comment, repost, recommend it to those who may be interested or sign up yourself.
http://brineangels.com/14-days-to-bust-your-language-barrier/