French here.
Struggled hard in English classes for many years, until one summer where i watched the Lords of Rings Trilogy long edition DVDs i was offered at christmas. I watched it first in french, as i always did before. But because i had nothing else to do afterwards, i watched the bonus discs. Bonus discs that where all in VOST. And by watching them, i realised that many scenes and dialogs sounded much better in english (especially Aragorn's speach before attacking the Black gate in the third movie). So once i was done with the bonuses, i rewatched the movies but this time in english with subtitles. And then i watched them with the actors commentaries. And then i watched them with the directors commentaries.
At the end of that month of Lord of the Rings marathon, spending hours and hours hearing people speak english, i was already much better at it. And then i started watching all my movies, tv shows and playing my games in english. A year later i didn't need the subtitles anymore.