I think one learns a lot by READING in English, because you learn grammar and vocabulary unconsciously, and to improve your pronunciation I recommend you to listen and read an audio-book. LOOK UP FOR ANY NEW WORDS AND CREATE YOUR OWN "DICTIONARY", by ordering the words alphabetically. I would suggest reading something every day, don't devote more than an hour, but be constant. You can pause at any moment and repeat what you just heard.
http://www.agendaweb.org/listening/audio-books.html These are audio books (graded readers) You should find one that you like, they are around 20 min long. Listen and read along, (better if you print the transcript).
http://www.manythings.org/listen/ These are articles and stories. Maybe you'll find some of them interesting.
Listening to songs and reading their lyrics can also help you, but not as much, as they usually have grammar mistakes and they are too colloquial.