First, cut one of the large panels off of a paper grocery bag. have your child paint the bag with as many different fall glitter colors as they like. Overlapping colors is encouraged and creates a pretty mosaic effect. Allow the paint to dry completely.
Cut the painted bag in half lengthwise along the seam if there is one. You should have two long pieces. Stack them on top of each other and cut them into thirds. You should have 6 pieces total.
Take two pieces and layer them back to back with glitter paint facing out on either side. Hold them together (or use a paper clip) and cut a simple leaf shape. Repeat for the other pieces, you should have 3 leaves.
You will want to create holes for your child to "sew" through on one side of the leaf. To do this, place one of the leaf shapes onto a piece of Styrofoam or a cork bulletin board. Use a toothpick to create holes starting from about 3/4" from the bottom point of the leaf, then one inch apart up to the top of the leaf, again leaving about 3/4" space at the top. Make holes for the leaf's veins as well.
Tie a knot in one end of the yarn and thread a child's safe sewing needle with the other end. Begin sewing at the bottom and work your way up to the top. Fo the veins last. Tie off the yarn in the back and cut off the excess.
NOTE: instead of a sewing needle you can use a hole punch to create the holes and wrap the end of the yarn with tape to make it easier to thread through the holes. If you go this route you make need to make either A) less holes for sewing or B) make larger leaves.
Next, parents should hot glue the top portion of the sewn leaf to the top portion of the matching leaf (make sure the glitter side is facing out). Glue half way down the sides, leaving enough room to add the stuffing.
Have child ad small amounts of cotton batting until the leaf is stuffed. Parents should hot glue the leaf closed.