* Travel and/or live in countries where your target language is spoken.
* If you haven't done so already, start using books and textbooks meant for native speakers of your target language. For example, Strunk and White's Elements of Style is a style reference book I had to use when I was a writing student at the university.
* Continue to increase your vocabulary by focusing on areas of interest. Learn just like a native speaker. For example, are you interested in sciences? Biology? If so, do you know all the vocabulary to talk about anatomy and physiology? Are you interested in chess? If so, do you know the names of all the chess pieces in your target language? The names of certain moves?
* Do you read the news from the countries that speak your target language? This way you'll keep up with current events and be able to talk about those things with a native speaker.
You have reached the so-called Intermediate Plateau, a point where most learners feel they have not been progressing much. Two simple ways to break through this plateau include:<o:p></o:p>
(a) Exposing yourself to a lot of English (along the lines of what Peter and Carmen mentioned above).<o:p></o:p>
(b) Noticing where you're getting it right and where you're getting it wrong. For instance, start writing notebook entries and pay close attention to the suggested corrections. <o:p></o:p>
"Advice" "advise" is to advise someone.
I don't know. I'm amazed at how good everyone's English is. I would recommend watching English/American TV and reading books. Progressing to an advanced level is mostly about vocabulary and the nuances of the language.