Every designer will tell you that curtains make every room—but only when chosen correctly. When it comes to window treatments, it is important to choose the colour and the fabric wisely.  Fabric is an essential part of choosing curtains, since the material will dictate how well your curtains function and hold up over time. "If they're too heavy, they may not fold crisply when drawn; too light and they may not fall well," says designer Suysel DePedro Cunningham of Tilton Fenwick.