I think, if you really want to learn. you must teach. the only reason that i learned cases was because i had to teach somone. i knew verbs, and he was like. ok lets start cases. so i said OK! hold on, let me... think up some sentences... yea, that's it ... sentences... (meanwhile i was typing in google "Learn russian cases".) so, i was actually forced to learn with the person i suggest, you master the material first, then teach somone later, unlike me. but you never fully understand somthing untill you can teach it. the dude i tought, i'm sure doesn't give a Ф*ck about russian anymore, he was one of those "wow i saw a cool russian sign now i must learn for 2 days and give up" but hey 4 months later, i am better because of it, and i think, you will be too.