Choose a color palette. Study the couch and pull out a shade that you would like to build the rest of the room around. Use a color wheel to choose either a complementary color scheme -- one that uses colors from opposite sides of the wheel -- or one based on different shades of the same color.
Mix and match patterns and unite them with the same color palette. Pair your floral couch with an Oriental area rug featuring the same colors found in the couch. Highlight a sofa covered in chintz in a large floral pattern with wallpaper in a floral mini print and solid stripe. Be daring and flank your flowered couch with arm chairs upholstered in complementary plaids. Layer the windows. Hang sheer or lace curtains closest to the glass. Cover them with draperies in a stripe, check, toile or plaid pattern.
Tone it down. Let the sofa be the room's focal point by using neutral colors and muted patterns. Choose rugs made from natural materials like coir and sisal or opt for carpet in neutral colors like gray, beige and cream. Paint the walls a shade of white or a shade of the color you chose from the couch as the basis of your palette. For example, if your main color is light green, give the room depth by painting the walls sage. Pair the floral couch with leather club chairs or chairs upholstered in nubby linen or polished cotton in a complementary shade. Dress the windows simply with Roman blinds or bamboo shades.
Accessorize the room. Hang a garden print above the floral couch and place a table lamp with a hand-painted or leaded glass shade in a floral motif on a side table. Opt for black and white photographs in a more neutral room. Forgo typical flower arrangements and choose arrangements fashioned from nature like ferns, branches, berries, grapevines and vegetables and fruits to highlight rather than being overwhelmed by the floral upholstery. Toss a bulky cotton throw over the back of the couch. Choose a complementary hue to add color without the fussiness of a patterned blanket or afghan. Perk up the couch with pillows. Choose pillows in different shades of the main color for a more neutral look. Give it some pop by mixing in one or two in a print featuring a bright shade of the main color.