Choose a core solid color as a unifier. One way to give a room a pulled-together look with mixed patterns is to choose a solid color for the sofa and then pick up that color in the other patterns in the room. One example would be to place a red sofa in a room with pinstriped curtains and patterned fabric on the chairs in the same shade of red.
Vary the scale of the patterns. For example, pair bold wide stripes with small flowered patterns, or mix subtle pinstripes with large scale floral patterns. Two to three mixed patterns in a room can be attractive but avoid going beyond that number. Too many bold patterns together confuses the eye and makes a room appear cluttered.
Look for prepackaged coordinated sets in a home furnishings department or store. Home furnishing designers often offer mixed patterns in coordinated bedding. Even if you are not shopping for bedding, checking out these sets can provide a guide in choosing the right balance and scale for your own home designs.