A layer mask is used to hide portions of a layer and reveal portions of whatever layer is below it. You can modify the mask by using the brush tool and painting in either black or white.

A drop shadow can give depth to text or elements of an image.

With this adjustment layer, you can adjust the hue (color), saturation, and lightness of a specific range of colors in your image.

Radial blur simulates the blur you would get by moving or rotation your camera quickly.