Since the bed in a master bedroom has the leading role, the wall behind that bed is the supporting actor.
Here is a super easy, inexpensive way to enhance that wall using nothing but grosgrain ribbon and thumbtacks. I must admit it took a while, but because there's no mess or chemical smell, it can be done over a period of days while still sleeping in the room.
The first step was to draw light pencil lines to form the pattern. I used a level and ruler to do this. Next, I started from the top of the wall and ran the ribbon down to the floor, using a bit of double backed tape to hold things in place before I was able to criscross and insert a thumbtack. I did a diamond pattern but squares would also work.
I didn't want my thumbtacks the silver color they came in, so I pushed them into a piece of styrofoam and spraypainted them in a bronze color.
The paint color is Cappuccino from Restoration Hardware.