time to get your backing on your blanket.
while looking over the original blanket, now almost nine years old, i noticed there has been some slight uneven shrinkage between the front cotton pieces and the back flannel piece. therefore, i think that even if you don't wash the cotton pieces for the front, it is probably wise to wash the flannel before sewing, since it is more prone to shrink.
pin the two pieces together. you are now going to sew them together around the outline of the pieces with a 1/4" seam, making sure to leave a hole for turning. start sewing in the middle of one of the sides. sew around all four sides with a 1/4" seam. stop sewing when you get 4" to 6" away from where you started so that you leave a hole 4" to 6" wide, or just big enough to get your hand in.
before you turn the piece, clip your corners so they aren't so bulky, lumpy, and rounded. to do this, cut diagonally across the corner. cut right up to, but no through your seam.
time to turn the blanket right side out. stick your hand in the hole you left in your seam.