The New Game of Thrones Trailer Has Sparked So Many Wild Theories

"Don't fight in the north or the south. Fight every battle, everywhere, always. In your mind." These are Littlefinger's words, presumably to Sansa, at the beginning of trailer. Not only does it seem like an insightful peek into Littlefinger's personal strategy but it shows how he's whispering in Sansa's ear. He might be giving her the bigger picture and the secret to taking over the Seven Kingdoms.