Photoshop :: Realistic Shadows For My Fabulous Piggy Banks

having had excellent support from Sirus and Jut, I've mastered the sparkle effect on my crystallised objects Tried to look for add-ins but there were just too many, I guess I just stick with the star brush.

I am really getting into Photoshop but I guess I will have to be patient to learn all the little tricks

This is my draft postcard for my piggy banks and I think they look great in this background. Problem: I would like to make them sit on the piles of coins realistically, i.e. some good shadow must be added.

Unfortunately drop shadow option did not help... still looks superficial. I added a bit of blur effect on piggies which are behind the picture. Still, they don't seem to fit into the picture well.