Okay, Here's my first attempt at a simple tutorial...
I love these simple to make Nursing cover sheets for breastfeeding Mom's. You can buy them from all sorts of places like here or here.
I have made quite a few of these. They are SOOOO simple and easy to make, inexpensive, and are a nice gift for a new Mom. The nice thing about nursing sheets is that they are thin and can easily fit into your purse or bag without the bulk for quick cover where ever you are. I used 100% cotton fabrics for the ones I made, but you could use a nice cotton/poly blend. In order to make one you need only 3/4 yard of 45" wide fabric and a piece of plastic canvas with the smallest grid you can find. The canvas I bought was 13 1/2 inches in the longest dimension. You really don't want it shorter than 13 inches or longer than about 16 inches. I found a sheet at Hobby Lobby for 89 cents. I don't know what other people use to make the stiffer window, but this was what I came up with and it works well.
Cut fabric to be 38 inches wide by 26 inches. Also cut a piece that is 2 inches wide and 20 inches long to make the neck strap. Fold over the sides and bottom edges and sew to finish the edges. Cut a strip of the plastic canvas that is at least 1/2 inch wide, I like 5/8 inches wide. Make sure you trim any sharp edges off the canvas strip with your scissors. Center the canvas on the top edge, fold over fabric edge, tuck under canvas, and pin before sewing hem edge.
To make the neck strap fold fabric strip in half lengthwise and press. Open strip and fold outside edges to the center line that you just made when you ironed the strip and then fold together so that outside edges of the strip are now inside and straight stitch the edge shut. Pin strap to the cover sheet on the top edge at the ends of the plastic canvas, try on to ensure proper length of strap. I find a finished strap of about 18 inches to be most comfortable. You can sew both ends of the neck strap in place or you can add a snap, button, or Velcro to one end of the strap if desired.
Good Luck! Hopefully this all made sense! :)