Some other options:
duplicate the layer you want to shadow and drop shadow the underneath layer
erase parts of this duplicate layer to adjust to your liking (erase tool with a very soft edge)
the same object but then in black.... make it transparent... skew and distort till you start to like it.... than some motion blur.. experiment with the direction etc.
don’t always try to make it accurate.. a real shadow is most of the time not as sharp as you would like to make it…and almost never realy black…. Use a few shadows sometimes(more than one light) etc. etc. etc.
the illusion is what counts I think, sometimes illusion looks more real than the real thing