While some of the default presets are of course helpful, the real power in this palette is creating your own tool presets. Select the crop tool again, but this time, enter your own values in the fields at the top of your screen. To create a new crop preset out of these values, click the “create new tool preset” icon at the bottom of the tool presets palette. This icon is highlighted in yellow in the screenshot. Photoshop will automatically recommend a name for the preset, but you can rename it to fit the use. This can come in handy if you are often cropping images to the same size for a client or project.
Once you understand the concept of the preset, it is easy to see how helpful they can be. Try creating presets for a variety of tools, and you will see that you can save any combination of variables. Using this feature will allow you to save your favorite fills, text effects, brush sizes and shapes, and even eraser settings.