Using sheer curtains layered below thicker curtains helps to create an anchor out of the window. The thicker curtains on either side provide a frame for the bed and the sheers afford a certain amount of privacy and they keep they scare black window effect from happening at night. It makes the bed look like it's supposed to be in front of the window instead of awkwardly fighting with it for space. Have you tried this at home? How has it worked out?
Image from Houzz.