english is my second language. i read and watch especially a lot of movies or tv series in english. watching movies really help because you are exposed to their slang and the way they talk (how to portray different emotions through tone of voice).
When I was in Germany, I found that my German improved by speaking with the German people and watching television in German. (Hint: Don't watch the news. The broadcasters speak too fast!!) Watching movies is also a great idea. If you have Turner Classic Movies or the MGM channel, there are some great old movies that could really help you. You can improve your English without having to learn the slang that is prevalent in all of the movies today.