Skewing the Drop Shadow filter to create a more realistic
looking shadow.
Select the object with the shadow you want to
skew.
Duplicate (select Edit > Duplicate) the source
object.
Select the duplicated object, and skew it using the Free
Transform tool (Modify > Transform > Rotate
And Skew).
Apply the Drop Shadow filter to the duplicated movie
clip or text object. (It will already be applied if the object you
duplicated already had a drop shadow.)
In the Filters panel, select Hide Object to hide the
duplicated object while leaving its shadow visible.
Select Modify > Arrange > Send Backward to place
the duplicated object and its shadow behind the original object
that you duplicated.
Adjust both the Drop Shadow filter settings and the angle
of the skewed drop shadow until you achieve the desired look.