Here's my story about English and Japanese. I started learning English in preschool and kept learning in till I graduated from college. I liked to study English but my real skills came from playing pc games and watching MTV. I used to watch about 2 hours a day when I was 15 or so. Basically playing games and watching someone speak that language helps with comprehension a lot.
I started learning japanese in college, there were 4 lessons per week, I was doing well with the grammar but spoken part was kind of stuttering rather than fluent speaking. So after 2 years of study one day my japanese instructor asked me a favor: She wanted me to help her friend's daughter study english. The girl spoke very little English. I was expected to teach that girl English in Japanese. At first I couldn't decide if she was playing a joke on me to see my reaction. When I realised she was serious, I told her that was practically impossible as I was not fluent in japanese and it might have been a problem. She just said "I believe in you, you'll do well". I said "What the hell let's give it a try, at most I'll fail miserably and have a story to tell how I pissed off an entire japanese family".
So, for 4 hours a week, I started studying with this girl, aged 12, with only a small english-japanese dictionary in my hand. She also had a similar dictionary, but it was digital and able to convert between kanji-hiragana-katakana and English. Probably it was from the future and could read also read our thoughts. Anyways vocabulary wasn't a problem but communication was. I was speaking slowly when I tried to explain basic English grammar. But day by day, my speaking got more fluent and after about 3 months or so, I was able to read a basic english text and translate it into japanese simultaneously, sentence by sentence. I guess the lesson here is sticking with the practice on an ongoing basis. I want to stress that 9 months of study with that girl advanced my japanese much further than the previous 2 year study as I was actively speaking most of the time.