Using 1 yard of fabric, I made two car organizers for each of my boys. I bought a half yard of turquoise, and half yard of lime, and used both to mix and match. This fabric is a little heavier than normal, but still only $4 a yard at Joann Fabrics.
First I cut out the pieces I wanted and layed it out.
I hemmed all edges under first, then attached the outer pockets, like this one made for little toys.
When the little toys pocket and the pencil pocket was sewn on, I then sewed the bigger pockets on. The top left pocket has 2 pleets in it to make it more spacious to hold a sippy cup or bottle.
I sewed a thick wide shoelace to the top to hang around the seat, then I ended up safety pinning the sides and bottom to keep it really secure and to save leg room.