Paint the tall, rounded wall in a dark color if you want to minimize the height of the wall. Select a wall color that is two or three shades lighter than the color on the other walls if you want to draw attention to the space.
Place large furniture in front of the tall, rounded wall instead of fragile, diminutive pieces. A wooden bookcase is much more effective than one with a metal frame and glass shelves.
Hang large wall art with curving lines, such as wrought iron scrollwork. This accentuates the roundness and fills the expanse of bare wall, yet it doesn't add too much bulk. Another idea is to hang a grouping of pictures. Choose pictures that have a theme or colors in common, such as many black-and-white photos or a series of floral pictures.
Mount a curtain rod approximately 6 inches to 2 or 3 feet higher than an existing small window on the tall, rounded wall. Once you add the curtains, it provides decor that is more suitable to the large expanse of wall space. If you don't have a window in the area, but there is one on the opposite wall, consider hanging a mirror to create a faux window. Mount a curtain rod and curtains above and along the sides of the mirror. This brightens the room and adds a decorative look to this wall.
Place a decorative room divider or screen in front of the tall, rounded wall. Often, these screens are angular, and this detracts attention from the odd-shaped wall, particularly if it has a large print on it. If the screen is a solid color, position an unusual floor lamp or a tall, potted plant near one side or directly in front of it. This adds interest and texture to the area.
Hang a wallpaper border so it is near the ceiling of the other walls. Continue the horizontal line of the border across the tall, rounded wall at the same height. This helps to draw attention away from the rounded section. Another option is to use crown molding.