Back To Back To The Future

Back To The Future was first released thirty years ago today. Of course, the most significant date in 2015 is October 21st, when Doc and Marty arrive to help his not-yet-conceived children and he acquires a hoverboard. (Still waiting...) Anyway, the original is pointedly filled with 1950s nostalgia while also undermining plenty of it, while the 80s still looks fairly normal apart from the bodywarmer. Compare retro-80s stories being made now. And plenty of then-modern 50s films, for that matter. How do you evoke an era without overdoing it?