I'd say that my mainly resource is the network. Through Internet i have found a great deal of resources to learn firstly English and then German. Initially i started learning grammar from a couple of websites that kindly teach you grammar for free, then i added some others resources like pdf books, tv shows/films with subs in English and online games where i could meet some native speakers. Now for learning German im trying to do the same and besides i'am constantly searching new resources in order to improve my learning and understanding of the language (in my search i found duolingo wich is really useful for the begginer level, flashcards, memrise, forums and blogs like this...).
I find that people don't know yet the truly potentiat that the net has for learning. At least i didn't until i started this journey.