Here's a basic How-To for making your own customized valances! They are non-functional, meaning that they don't draw up and down, which makes them quick, easy and inexpensive. I like to mount these atop windows that are already fitted with blinds so they can hide the top of the blinds and your window will still have coverage flexibility.
Start out by measuring your window. Take the width of your window (including trim) and add a total of 4 1/2 inches (which gives 2 extra inches per side, plus 1/4" seam allowance). If you want more fabric on either side of the window, add more inches to this measurement. This is your cutting dimension for the width of the window. Now decide how tall you wish to make the valance. I usually place my valances 4 inches down from the top of the ceiling. Having it so high provides a nice sense of height in your room. So start at the top (where the top of your valance will be) and measure down to about 5 to 10 inches below the top of your window. Take that measurement and add another 12 to 15 inches so you will have plenty of extra fabric to gather or roll once the valance is in place.
For valances such as this one, you will also need to cut 2 rectangles of fabric to cover the ends of the valance support. I made mine about 5" x 7" in this example, but in retrospect, for a valance as big as this one is (the cutting dimensions were 44" x 40") I would recommend making the rectangles 6 x 8 and orient them differently (more on that later).
A word about fabric: Heavier-weight home dec fabric works best for these valances. If the fabric is too lightweight and flimsy, it will tend to sag and hang unevenly.
Now that you have your cutting dimensions, cut one each of both your valance fabric and liner fabric. I recommend cutting your valance fabric out first, then placing it face down onto the right side of the liner fabric and cutting the liner fabric out to exactly the same dimensions. Do this for the valance piece and the 2 little side pieces.
Pin the sides and bottom of the 3 different rectangles, and stitch a 1/4" seam down one side, along the bottom edge, and up the other side of the rectangles. Leave the top side open.
Trim the 2 finished corner edges on each rectangle as shown so that when you turn the fabric right-side out the corners won't have excess bulk. Take care not to get too close to the stitching, but trim enough away so that it won't bunch up when turned.
Turn each rectangle right side out, pushing and wiggling the corners to get precise tips. Press with iron, wiggling the edges so that the fabric and the liner are exposed to their maximum dimension right to the stitching line. I lick my fingers (to create friction) and work the fabric back and forth with my fingertips while ironing the edge to accomplish this.
Mark where you want the top of the valance to be, and install 2 right-angle brackets onto the wall, about 6 inches in from each side of the window.
Hint: Don't use the little screws included in the bracket packet for installing into the wall unless you use sheetrock anchors. Instead, use a sheetrock screw that's about 1 to 1 1/2" long. Since these are decorative valances only and won't be tugged on, it's not necessary to drill them into a stud - but the tiny little metal screws won't even keep it in the sheetrock.
Measure the side-to-side finished dimension of your valance and cut an inexpensive firring strip (or equivalent) to that dimension. Place it on your brackets to make sure it's level and the width you want it to be.
Now take the little rectangles and staple them (using a heavy-duty upholstery stapler or equivalent) onto the ends of the stick as shown. In this example, I oriented the rectangle horizontally so that it was wider than it was long. I recommend orienting it the opposite way for your valances, as I think it looks better to have a longer valance cap than these produced.
Once the top is stapled, tuck the corner under itself and staple the sides of the cap onto either side of the wood as shown.
Now staple the top (the unfinished edge) of the valance onto the stick as shown. This is the top of the valance, and it's so high up that nobody will ever see the staples. Unless you're making these for windows on very tall walls that will be visible as a person goes up and down stairs. If that is the case, staple the fabric to the thin backside of the stick instead.
Now you will need to sew the bands of fabric that hold up the valance excess at the bottom. I usually wait until I get the valance stapled to the stick before deciding if I want one or two bands, and how wide they should be. If the window is greater than 30" wide, I recommend using 2 bands instead of one. These bands were cut to be 7 1/2" wide x 44" long. With right sides facing eachother, I sewed the long edges together (with scant 1/4" seam) to create bands that were 3 1/2" wide and 44" long. Turn right side out and press so that the seam is centered in the middle of the back of the band as shown.
If you are using only one band per valance, I recommend cutting it slightly wider: either 8" or 8 1/2" wide to yield a band that is about 4" wide.
Staple the band(s) onto the top of the valance as shown, making sure it's centered on the valance.
Place valance onto the brackets, making sure it is centered above the window. Screw into the wood from the underside of the valance as shown.
This is what it will look like at this point.
There are a few things you can do to the valance at the bottom; either roll it up or bunch it up. I'll show you the rolled method first.
Take a wrapping paper tube that is a few inches shorter than the width of the valance on either side and simply roll it up inside the bottom of the valance. If the valance is wide (like this one is) it's helpful to tape the bottom of the fabric to the tube to help you get it started evenly. A tube with a wider diameter looks better, but I didn't have one on hand so this skinny one is what you see.
Once you get it rolled to the height you want, simply take the raw ends of the bands and safety pin them to the back of the valance at the correct height. It's very helpful to have a friend hold the roll while you're doing this. If not, you can tape or pin the roll in place on the ends until you get the bands in place. This is tricky - I speak from experience - so I really recommend getting someone to help you, especially the first time you do this!
This valance looked a little boring to me, so I added some black ribbon to the bands with double-sided tape attached to the backside of the ribbon for added interest. There are several black accessories in this room so the black ribbon made the valance relate to the rest of the room better.
Since I wasn't crazy about the skinny tube on such a large valance, I took the tube out (without unpinning the bands) and just arranged the folds in the bottom of the valance as shown. It created a softer look that looked better with the dimensions of this valance.
These bands (or sashes) were done differently as well. I used sashes on the front and back of the valance (so each valance requires 2 sashes), finished the ends on the diagonal, and tied a knot in them to establish the valance height.
I created the diagonal by folding the strip with right sides together, then I cut the open side (with the raw edges) 2 1/2" shorter than the folded side.
I sewed along the long edge and the short angled edge, then trimmed the angled edge and the corner very close to the stitching to reduce bulk. After turning right side out, coax the corners out into a nice tip and press flat using the same method as described above for pressing the valance.
This is the same style of valance as the black and red ones shown above, except this one is mounted on the outside of the window frame. I didn't use the metal right angle brackets to attach it to the wall; rather, I simply screwed the wood into the sheetrock (the stick was turned so the wide flat part was against the wall) and wrapped the fabric around the 1/2" edge of wood that was showing on the ends.
This was Eliza's room in Hawaii. You can see a bit of a valance peeking at you on the right. This one was slightly different in that I made a little "skirt" thingy to drape over the top of the valance, and I used grosgrain ribbon for the bands. I also used a printed quilting weight fabric for the liner fabric, which adds more interest than just a solid color.
As you can see, the possibilities are pretty much endless depending on style and pattern of the fabric you use and how you choose to embellish it. Now go get sewing and best wishes to you! :-)