Actually, I don't. The fabric you chose is just perfect and adds some texture even though the shape is simple. However, if YOU don't like it, think about cutting up some slivers of the lighter color (in hair strands) and machine appliquing them over the hair. That would add some texture. Or, you could use a satin stitch with the lighter color and just stitch some strands into the hair. Personally, I would leave your portrait just as it is because I love it.