Let me get serious for a moment. I suspect I have a couple of years on Amy, and that I'm at least twice EF's age (and maybe three times; I can't tell). Point is ...
I've had more years to learn vocabulary, to pick up idioms, and generally learn language. We learn most of our language in our first ten or twelve years, but that's no reason to stop learning. Once out of formal education, reading is our primary arena for learning, and the best thing is to read a wide variety of authors. I think I first saw soi-disant in Stranger in a Strange Land. I'm not sure where I learned to invert 'if he ever' into 'if ever he'. Maybe it was in Lerner&Lowe's If Ever I Would Leave You, a song, but I probably regarded that as poetry and did not consider it for use until I saw it somewhere else--and that somewhere might have been in an essay.
Good essayists and good history writers are good language teachers. Note that many essays are position papers on editorials. You don't have to agree with either Thomas Friedman or Victor Davis Hanson to learn from their writing. And in fiction, Dorothy Sayers is an education in herself.
With rare exceptions, you won't get these lessons from movies, television, and radio.
I'm blessed with better-than-average language skills: about 70th %ile on the GRE so many years ago. I suspect this is true of everyone here. These days I don't read enough--but I do continue to read. I just wolfed down Susan Cooper's The Dark is Rising a few weeks ago--the entire set. And of course, I read a fair amount of material from authors here. Even as I argue for someone to move to a plainer, more economical style, I may be learning elegant expression for those times when I need it.
To quote the author of How to Write 240 WPM in Pitman Shortand, you can do it too!