Before starting the curtain I measured the length of the windowsill and made my curtain the same length.
The fabric that I planned on using was actually purchased about a year ago. I saw it at Joann Fabrics and really wanted to use it somewhere in the house. I only bought 3/4 of yard, so that's all I had to work with. I would have liked to use more, but I was using what I had around the house. Remember, I am trying to redo the bathroom on $100 or less. I laid my fabric on top of my lining and cut the same amount of lining. Once I had my fabric cut, I turned right sides together and hemmed the bottom. Then, I separated the lining from the fabric (at the hem) and measured 1 1/2" and pinned the bottom and sides. Then hemmed both sides. (DO NOT HEM THE BOTTOM)
Once the sides were hemmed, I removed the bottom pins and turned the fabric right side out. I ironed the bottom to lay flat then measured 2 1/2" on each side, folded over the fabric and ironed the sides over. This creates the crease on the side when you mount the curtain to the board.
This is where I stopped taking pictures and was trying to figure out the math involved in getting the pleats even on both sides. This is also when I realized that my original measurements where for a 1x3 board and not a 1x4 board, which is what I had. So, I ended up having to remeasure everything over including the sides that I just ironed. I went back and measured 3 1/2" instead of 2 1/2" and so it would cover the depth of the board. I'm not even going to try and describe the math involved in getting everything centered. Basically, you want to find the center of your curtain (minus the 3 1/2" on each side) and then measure and pin where your pleats will be. When you overlap your fabric to make the pleats you end up with 41" (This is the length of the board. The 3 1/2" on each side that I ironed will wrap around the side of the board. The total length of the curtain is 48")
Our "family" chop saw was at my brothers house, so I very nicely asked my husband to cut the piece of scrap board down to 41 inches for me.
After I had my board ready, I cut lining fabric long enough to cover the board and attached the fabric with a staple gun. Wrapping the board makes the curtain look more finished when it's all done. Trust me, it's worth the extra few minutes it takes. After I had my board wrapped in the lining I attached the curtain to the board with the staple gun.
You can see in the below picture where the side of the curtain wraps around the side of the board. This way when the board is hung the hardware and window frame are all hidden. I could have left the curtain as is, but I wasn't happy with the simple box pleat and decided to draw up the sides.
I made a small stitch at the seam where the lining and fabric meet. Then measured up 4 inches, pulled the fabric together and made a few stitches. I did this one more time until I was happy with the length.
I was so excited to get the curtain hung that I haven't yet patched the holes in the drywall from where I took the old curtain rod down. Hopefully, I'll get that done this weekend.