Paint each half of cardboard egg box with desired color of acrylic paint. Be sure to choose paint a shade brighter than the desired final color as the glass glitter will give the egg a frosted effect and will tone down the color a bit.
Once paint has dried, use a 1-inch foam brush to apply a thin layer of slightly watered-down white glue onto each half of the egg box.
Sprinkle glitter onto egg box halves with a spoon. To conserve glitter, work over a tray covered with a piece of craft paper that can be used to pour excess glitter back into the container. (Be sure not to rub your eyes while using this glitter because it's made of real glass!)
Using a hot-glue gun, affix velvet ribbon, trim, and flowers to egg box as desired.