Previously I persuaded my wife to only speak to me in her native language every Thursday afternoon/evening. That helped a little, but only when I moved and was surrounded by the new language did I really get better.
It took me months to learn to hear AND pronounce the difference between "o" and "ö", and still I get it wrong at times.
When learning Indonesian my sole company for most of the day was my korean flatmate, who had no english. We evolved through some hilarious pidgins to fluency pretty fast.
Necessity is the mother of invention