Velvet ribbon in 3 shades "stitch-witched" or hot glue'd to inexpensive white panels. You could use grosgrain ribbon too!
Diamond trim. Make diamond template out of cardstock (measure, measure, measure!). Use template to trace pattern in straight line on panel. Paint diamonds with fabric paint. Wouldn't this be cool in Black/White or Chocolate/White?
Free hand sketch branch & leaf design. Paint over design with fabric paint.
Cute idea for kid's room using stencils and fabric paint! Helpful hint -- use spray adhesive that is repositionable to adhere the stencils to the fabric temporarily. Use a stencil brush to apply the paint. Dab all excess paint off the brush until the brush is almost dry. You may have to do several applications using this technique, but it will ensure that you don't have "bleeding" underneath the stencil.
(photos courtesy of BHG)