Spend at least one hour everyday listening to news or discussion programs such as NPR (National Public Radio) news or BBC (British Broadcasting Corporation; the World Service or Radio Four are best) news. It's hard to understand what they are saying when you first begin to listen to them, but gradually you'll get used to the speed and tone. Then you can get a brief idea of what they are talking about, although you can't get the detail. You don't need to listen to the radio for an whole hour at once. It's best to spend twenty or thirty minutes on listening separately.
Learn the phonetic alphabet (pronunciation symbols). This can help you pronounce correctly, and it's necessary to speak with the correct tone if you want to make some friends with native English speakers. This is a big deal for non-native English speakers.
Make friends with native-English speakers. This is the most difficult task because of the difference in culture, but you can't really master English unless you can communicate with a native English speaker fluently. You have to know enough things and have good listening skills if you want to have good conversations with an American or Briton. Remember to ask a lot of questions to keep the conversation going. When someone asks you a question, give more than just the basic information. For example, if someone asks you "Do you like living here?" don't just answer "Yes" or "No," but tell them why, too.
Watch some English TV. TV is the best and most inexpensive teacher to learn real English. Not only you can learn formal English from news or debate TV programs, but you can also learn everyday English from soap operas and sitcoms. Be careful because too much jargon or too many idioms make your speech