One of my many personal quirks is that I don't like the look of the top of a curtain rod when it is a gathered rod pocket type. I don't even like the look of a shower curtain, and usually add a valance over the top of it.
I knew I had seen DIY cornice projects online, and after a search, I found this project: http://www.melaniehamdesigns.com/cornice-board-diy-window-treatment/. My window is wider than the windows shown on the project, but since I already had the batting, and duct tape, I decided I could risk $2.00 on foam core boards from Dollar General!
First, I started by measuring my window, and deciding how tall it should be, as well as the depth of the side panels. I then traced the lines on for cutting using a yard stick and pen, and cut them out with an eXacto Knife.
After cutting all the pieces (in case you are curious, my width was 78", the height of the board is 9" and the side panels are 7"), I taped the panels together with duct tape. I found that I had to tape all the way around the boards to get more stability.
After taping all the boards together, I added a very thin batting over the entire piece. I also used duct tape to secure this.
Next I added the fabric over the top of the batting, and taped it in place (sort of like wrapping a really awkwardly shaped present.) Because of the length of the piece, I was worried about stability, so I used left over foam across the back where the seams were to give it additional stability. Because foam core weighs so little, I wasn't worried about weight. I also added a couple of tape "tabs" to the end of each side to have something to nail through to secure the cornice to the walls.
Once it was finished, I used four nails on each side to attach the cornice to the wall. I anchored them by the wall by nailing through the cornice at an angle. Nailing though foam core is a breeze.
As a final touch, I added some rhinestone trim (matching the trim on the lamp shade) with hot glue. I purchased the trim online at Save-on-crafts.com.