Now that your shadow is on a separate layer, you can manipulate it as you would any other layer. This one fades to nothing at the top and left corners, and has been softened gradually along the whole shadow to blend. Once you have the technique mastered, you can use it for more design elements. We took the idea from the menu and created a matching dividing line, like the one below, which works well as a page divider. You can also gang the lines together and use them to form a menu.
Irregular shapes are no problem when the shadow is created automatically and then separated.
The bottom version of this image has had the same texture added to the shadow as was added to the background. A shot of the textured shadow without the background is shown below. Once the impact of being able to do whatever your little heart desires with a shadow layer hits, you may go running for information from the art world on light and perspective. I've included an irregular shape at the left. When the shadow command is doing all the work, it does not matter how complicated the shape of the shadowed object is.