Sew and hem the repair fabric, remembering to enclose all seams. Measure the fabric against the roller shade before you sew the second hem along the fabric’s width, just to make perfectly sure that the repair fabric’s width will exactly match that of the roller shade.
While it is technically possible to sew the fabric directly to the roller shade, I didn’t want to stress my apparently brittle and easily torn shade, so I chose to hot glue the fabric to the bottom edge of the shade. If you use a high-temperature glue gun, you’ll have a little more time to work with the glue before it solidifies, although you’ll need to be careful, because the glue at that temperature is hot enough to burn your skin and leave a scar (of which I have TWO!).