Part 1: Creating a Colored Ball with a Gradient Shadow
1. Make a circle with the Ellipse tool, holding down the Ctrl key to constrain the ellipse to a circle. Make second ellipse, slightly larger than the first, as shown in the example above. This second ellipse will become the drop shadow for the ball.
2. Select the Fill tool. 
Change the type of fill from Flat to
Circular.
Drag a blue swatch from the color palette and drop it on the arrrow as shown below. Adjust the position of the highlight for the ball by dragging the fill's center to the upper left edge of the ball.
3. Select the Fill tool again, and change the type of fill from Flat to Circular. The shadow shown in the example has a dark gray center gradating to white. You can adjust the appearance of the gradation by dragging the handles for the fill.
