A valance can tie together other patterns and hues in a room. The key is in taking careful measurements; the width of the curtain rod, the depth from the wall, its length accounting for top casing and bottom hems. Use a contrasting fabric to line your valance cutting it longer then the finished length. This will allow the contrast to be visible, like a band across the bottom of your valance. Repeat the contrast fabric from your valance on a throw pillow, using the main valance fabric as a cording detail around your pillow.
When selecting fabrics for a project, make certain they are made of the same fiber or fiber blend. If you choose a fabric that can be machine washed, preshrink it in cold water.
When using two different fabrics together, choose fabrics that have at least one common color. One can be a stripe and the other a floral as long as they both share common colors. Two floral and two plaids can work together effectively if one color predominates on both fabrics and if the patterns have sufficiently different scales.
To determine if a particular fabric is right for you, purchase a yard and hold it up to your window or lay in on existing furniture. If it does not work, use it to create a decorative pillow instead.