Instead of placing furnishings such as tables or sofas against the wall, look for arrangements that put them at the center of the room. In a living room, you can put two loveseats opposite one another for an intimate gathering area. If space limitations require you to put seating directly against the walls, consider comfy chairs instead of sofas; the narrower the item you place against the wall, the less space you will lose.
If you absolutely need to get some storage space out of your rounded walls, use track-mounted shelving instead of bulky bookshelves or cabinets. Mount the tracks following the normal instructions and, instead of regular shelves, bring boards to your local lumber yard and have the backs cut into appropriate curves. To make the most of your space, make your shelving tall and narrow. If you have a large room and a broad, curved wall, you can install custom-built shelving that tapers at either end. While the tapered ends won't be practical, they add a sleek, decorative flourish to the room.
Instead of trying to hang paintings on the walls, look for decorative options that don't require any straight lines. For example, you can add color to a room's walls with accent curtains around the windows. To create beauty in a windowless area, use sculpture instead of wall hangings. Set a slender pillar with a piece of art mounted on top; the solution takes up relatively little floor space and adds some interest at eye level. Hanging plants also add some life to bare walls; no flat surfaces are required.
Often, rounded rooms are relatively small turrets in older homes, particularly Victorians. If your rounded walls are part of a small spare room, think imaginatively about possible uses. Drop any fixed ideas about using the round room as a guest bedroom, as beds are resolutely rectangular, whatever their size. On the other hand, a round room can serve as a studio or home office, which simply requires space for a desk and some storage. Round rooms also make excellent playrooms for children, where you can use lots of informal and amorphous storage devices, such as hammocks for stuffed animals.