Match the window curtains to the colors on the walls. Take a paint chip that matches the paint or a swatch of the wallpaper on the wall with you while shopping for your curtains. Hold the paint chip or wallpaper swatch up to the curtains to match the colors of the fabric and the walls.
Take a digital photograph of the room you will be hanging the curtains in. Compare the photograph to the curtains to find a fabric that matches the color scheme and the style of the room.
Bring samples home. Visit a home supply store and select a variety of samples that you think will go with the color and look of the room you will be putting the curtains in. Hang the samples up over the windows. Choose the sample that best matches the look and color scheme of the room.