Miscalculated Subway tile spacing What should I do?
Pity the tiles are laid: I'd have run full tiles down from the ceiling, and got rid of the cuts you put to line up with the top of the window architrave. You could have packed out the top of the architrave almost invisibly with timber and paint.
As it is, fit a small timber trim/coving, call it what you will and paint it as if it's part of the ceiling. Only you will notice it.