I prefer learn and improve my English in the internet, because I have a lot of opportunities there. I watch video-lessons on Youtube, read articles, listen to interviews or music. I also learn English on different courses. For example, two weeks ago I was at English course where teacher explained us how to sound like a native speaker. It was useful and cheep course. I also recommend everyone to read books in original language, because it really improves your reading and writing skills. I reckon, that these ways of learning English the most useful.