So after browsing many pictures of valances, I took some measurements, sketched what I wanted, ordered some fabric off ebay, and made a pattern. My husband had the great idea of folding a piece of paper up to help construct the pleats in my mind.
I used cotton quilting for the front and muslin for the back. The iron really is your best friend in a project like this.
I ran into a little trouble when inserting the curtain rod through the top. The valance must be pleated first and THEN folded over (as opposed to folded over and then pleated) because you can't make the curtain rod fit the shape of the pleats, no matter how hard you try, he he. Luckily I hung the first valance before finishing the others, so I only had to unstitch one.