First, decide on the centerpiece colors. Are you creating a centerpiece for a specific event or just adding a pretty decoration? The answer to this question will give you some direction. If the occasion is an Easter dinner, for example, consider using pastel-colored flower petals.
You don't have to use a single color for the entire centerpiece. Each ball can have a different color or they can all match. The sewing pins, however, will act as the flower's center and should contrast somewhat for impact. Dark blue pinheads with light blue petals are one possibility. Dried flower petals or heads, instead of silk, may also be used.
Lay some newspaper on a flat surface for protection from the craft glue. Pour some craft glue into a disposable plastic cup or bowl. Using a soup can as a base for the Styrofoam balls makes it easier to keep the balls steady while you apply the petals. Set the largest ball on the largest soup can.
Using the foam brush, lightly apply a layer of craft glue to a 3-inch square area of the ball. Begin setting the petals on the glue. Create a series of flower shapes using four to five petals for each, slightly overlapping them to cover any exposed Styrofoam. Add glue to any petal parts which don't lay flat. The centers of every "flower" must also overlap just enough for the sewing pin to catch all petal layers when they're inserted.
Continue adding petals around the Styrofoam ball until the entire exposed section of the ball is covered. Adjust the ball to expose bare areas. You may have to wait until the glue has dried completely before making this adjustment.
Insert the flower pins into the centers of each flower shape. Repeat Steps 1 through 5 for the other Styrofoam balls. Use the smaller soup cans as bases for the smaller balls. Allow the glued petals to dry completely before arranging them in a glass or crystal bowl. Set the largest ball in the bowl first, followed by the second largest, and, finally, the two smallest. This simple centerpiece makes a beautiful addition to any table.