I think it can be summarised in just one word: Practice! That's all you need. I don't know how long you have been studying English, but it takes a long time and lots of practice to master any language. So see lots of films, read lots of books and articles... gossip a lot with your friends! lol There are no shortcuts to improve your skills. Constant practice is what will eventually make you speak English like a "pro". I'd wish you good luck, but luck is not necessary :)