Wow......I was really thinking this thread was abandoned and forgotten..........nice to see there's someone that's regularly writing in it.........
My learning curve: school first, of course. I joined a post-school afternoon course since the basic school (elementari) and always paid great attention to English lessons in the following years.
In the years 2000-2006 I had a working experience which brought me to have daily relationships with stranger fellows who were speaking English only, and in 2005 I even had some working trip to USA.
All of this allowed me to blow off dust from my school English and to make it a bit better than before.
The only serious problem I encountered is with the understanding of americans when they speak fast.........