Pick a Color, Any Color. Then Keep It.

Mac OS X includes its own built-in color picker that lets you choose colors in several different ways including a color wheel, RGB and CMYK sliders, and the venerable crayon color picker. If you create several colors and want to save them for use in other applications, you can do that, too.

You can store colors in the Color pane.

Many applications, including TextEdit, let you access the Color pane from a Format menu. Once there, you can pick colors for text and graphics, and you can save those colors for future use simply by dragging them to the well at the bottom of the pane.

Drag the bottom of the pane down for more storage space.

By default, you only get 15 spaces for storing colors, but you can add more. Just drag the bottom of the pane down to expose more color spaces -- up to 300, in fact. That should be plenty to store the colors you use most often.