At playgroup we made bells for the Christmas tree last week. They were made from egg cartons with a pipe cleaner as a hook & then the kids glued celephane & foil paper on them.

Get some contact paper, draw a picture on the non sticky side with permenant marker, then get her to stick celephane on the sticky side. Stick another piece of contact to seal the celephane in, then cut around your shape & you have a "stained glass" picture to put on the window. Do simple shapes like a bell, Christmas tree, candy cane or stocking so it doesn't matter what colours are where