Step 1: Collect Supplies and Measure
1 Bag that needs interior pockets
1 sheet of 12"x18" 7-mesh plastic canvas
1/2 yard of fabric; I used 2 flat quarters
1/4 yard stiff interfacing; I didn't use fusible web, but you could
Devices to put into pockets
Paper and pencil to take notes in
Snacks, in case you get hungry
Step 2: Cut fabric and sew the pocket strip.
Fold the second piece of fabric, the pocket fabric so that, when folded flat, the folded area is 1" shorter than your chosen devices. Cut this piece out - making it at least 5" longer than the backing piece. In my case, this was about 3" tall and 22" wide.
Cut one piece of interfacing the same size as the pocket piece. If you're using fusible web, iron it on to the wrong side of the pocket piece.
Place the interfacing on top of the folded pocket strip. Sew one of the short sides of the strip and the long side. Turn the pocket strip right side out and iron flat.