When you want to choose a new color as you create graphics, use the Swatches panel. The Swatches panel contains color swatches from which you can choose as you draw.
Swatches panel
To open the Swatches panel:
Choose Window > Swatches.
The colors in the Swatches panel also appear in the color well pop-up menus in the Stroke and Fill panels, Color Mixer, and the Toolbox.
Color wells in the Toolbox
Color well pop-up menu
To open a color well pop-up menu:
Click the arrow next to the color well.