Regardless of what your opinion of A Dance with Dragons is, I think its unanimous that the epilogue really sets the table for The Winds of Winter. My favorite little excerpt from the epilogue gave me the chills the first time I read it.
The white ravens of the Citadel did not carry messages, as their dark cousins did. When they went forth from Oldtown, it was for one purpose only: to herald a change of seasons.
And to think, I thought “dark wings, dark words” had an eerie ring to it.