Iván wrote:And I know talking to people is one of the best ways to improve, but that’s not my main problem. I’ve got many friends from abroad and fortunately I’m not shy at all, but rather I would rather like to start increasing my vocabulary in English because sometimes I think that I sound too basic.
I misunderstood your problem then. When people talk about "fluency", I assume they mean fluency in production, i.e. speaking and writing without having to think too hard about how to express themselves.
I think I understand what he means, because i feel the same sometimes.
I've been using English on daily basis for several years now, to the point that for some expressions, it takes me time to find them in French, just because I never had to use them in context in my own language.
I can talk and read and understand people with no issues.
However I still feel that I make mistakes in syntax and grammar, and lack some vocabulary, words that seem apparently very common for native speakers but that I've never heard nor used before.
And I am not even talking about the accent, although I've tried so hard to get rid of it.
I found that a good trick was that, if you are talking with someone, and that person is using some random word you don't know, even if you can kind of get it from context, still ask exactly what it means, so you can remember it and re-use it eventually.