Doing this post for my friend Julie, my sewing "lingo" is my own, I have no idea what the proper verbiage is for those that actually know how to sew.
The best type of fabric for the belly band is a thin fleece because it is soft against your dogs skin.
Cut two pieces of the same size fabric. The size will depend on your dog. I cut two pieces that measure 17" long and 6" wide (remembering the seam allowance of 1/4").
Then I line the two pieces of fabric up together (right side in)
Next, I sew three sides of the rectangle (1/4" seam allowance) leaving one 6" end open to flip right side out later.
After you flip the sewn piece right sides out then you'll bend in the edge of the open pieces of fabric and sew closed.
Then when you are done with that you can apply velcro to each end of your belly band. I use velcro with adhesive and although the package says it does not need to be sewn on I have found that to be NOT TRUE. If I don't sew the velcro in place it comes off in the wash so definitely sew it on.
I sew one line on each side down the full length of the belly band so it goes over the ends of the velcros and then I sew across the width of the fabric through the velcro also so it remains firmly in place.
This is what it looks like when all finished.