1. Live and work in a completely English-speaking environment.
2. Do some kind of sports, hobbies, or other activities with a group of English speakers.
3. Talk one-on-one with an English-speaking tutor a few times a week.
4. Watch movies, TV shows, and videos in English (with English captions or without subtitles).
5. Listen to English podcasts on a topic that's interesting to you.