based on my experience, i learned english a lot by:
1. of course, my fave class is english.
2. reading english books.
3. watching english movie or tv series.
4. tune in to english radio.
5. practice to speak english everyday with your friend or officemates.make a game, like there will be a consequence if you dont or if you forgot to speak in english.in that way, we have no choice but to speak the language.
hope this might help you.