The first year we were in our house, we agonized over our existing downstairs curtains. They were well-made and performed adequately, but the style was hopelessly outdated and not exactly our taste.
So I jumped in feet first and purchased double the number of panels I actually needed so that I could create my own valences out of the extras. I really wanted valences because I like the look of the pinched pleats at the top.
I measured a few inches down from the ceiling and hung the valence curtain rod at that height. I then measured from the curtain rod to just below the top of the window. I now have a measured length for the valence. I then took an extra panel and measured from the top down to the desired length. I think I really should have allowed an extra 6" for the hem, but in reality I only allowed about 4". I then ironed a crease to start the hem at 2", then another crease another 2" up from there. I then folded up the hem into the 2 creases and hand-stitched the top of the hem in place.
I then stitched as many valence panels together as needed to cover the width of each window. For the window pictured below, I actually used 3 panels for the width.