My level will always be that of a foreigner. I will never lose the accent, but I do have the ear to hear the accent of others. I can hear someone and know what area they are from.
It took a long time to learn, and I used my own methods. I learned to read first and speak second ( usually it is the other way around ) I read books on subjects that I would read in English, like aviation books, and that helped keep my interest high. It did produce a strange vocab , since I could say words like ‘wingspan’ before I could say things like ‘kindergarten’.