And once you get a shadow the way you like it with changing the color/distance etc. Make sure you save it!! I have one for papers, one for vellum, one for buttons, one for ribbbons, one for big 3-d elements etc.
Then go in and right click on the little f, and select create layer. Then your shadow is on its own layer and you can play around even more. Usually I add a slight wave to papers' shadows so they aren't perfectly flat, and I tend to warp a little the ribbons/flowers' shadows.
LOTS to play with with shadows!!
Here's the tutorial that I learned by (lots more out there I'm sure, but I love the pics she gives)
http://mistycatodesigns.blogspot.com...p-shadows.html