[jahn716]

Many of already waded in so not sure I can add anything different. However, here I go ;)

I guess for me the main question is, what do you mean by 'fluency?' Do you want to speak/be thought of as someone from an English speaking country? Or is it more a personal feeling that you want to be better?

For someone with an already high-level of English speaking and writing, I think the remaining barrier is more cultural than language. Like can you decipher common codes as someone who lives in the culture of that English-speaking country. And from my experience, a lot of that is broken up into two categories - 1. childhood identifications, things like education system, curriculum; regional, national milestone events, etc.; and 2. pop culture today, things like TV shows, current events, views on social, economics, politics, etc.

I think it's easier for the US case just because how pervasive American soft power is. But in any case, my feeling just from your post is that it's perhaps really more culture rather than language that you want to focus on.