Visit websites like MeetUp.com to see if there are English practice groups in your area. Peer practice and criticism is always valuable. Take a pencil and paper (or laptop) to record words and phrases you don't know when you meet with the group. Ask what they mean or look them up later.
Call local universities and talk to someone working in the international students office, and foreign language teachers if possible. They will usually know other foreign students practicing English you can work with. Ask if there are clubs set up to practice English, or English-speaking students interested in conversation exchange, where they would help you with your English in exchange for you helping them learn your language.
Search the web for websites like Livemocha.com and ConversationExchange.com dedicated to connecting people who can practice and peer edit each others languages. Connect with a conversation partner whom you can chat with over Skype. Again, remember to record words and phrases you don't know.
Watch TV. Find a show you like and want to keep up with, and record it. As you watch each episode, write down things you can't understand or words you can't make out to ask your conversation group or partner about later. When you've spoken to your group or partner, or looked the words up in a dictionary, watch again and see if parts you missed make more sense.
Borrow books from the library. As always, copy down words you don't know as you read. Start with children's books, also known as "easy readers." Then, try "middle grade" fiction, which are for elementary school children. After that, "young adult" fiction for older teenagers. Finally, try books for adults. Start with recently published fiction set in modern times, as fiction even 20 or 30 years old, or set in the past, will have slang no longer in use.
Search the web for free sites teaching conversational English. Many will have sound clips, videos or tips you can use. Bookmark them.