Applying a Gradient Using the Gradient Tool
To help you understand how to apply gradient in Illustrator CS3, begin with a basic shape: we will use a square. Press <Control><F9> to open the Gradient palette. Press F6 to open the color palette.
With your object selected, grab the Gradient tool from the toolbox.
Click on the object's path to reveal the Gradient Annotator. The gradient you used last will apply to the object. The annotator allows you to change the focal point, location, origin, spread, and angle of the gradient according to your needs.
The Gradient Annotator can be switched on and off using the Adobe Illustrator "View" menu. Just click "View" on the menu bar and then click show or hide.
Gradients can be altered by selecting the object containing the gradient and then choosing the gradient tool. You can change stop colors, stop positions, opacity, angle, aspect ratio, midpoints, and more.