Hi
On this tutorial, I will show you how to create a shadow that follows perspective and lighting.
1- Open up Photoshop and Open the image with the object want o apply the shadow to.
2- Extract the object from its background (If you do not know how to do extract something, search on google and you will find tutorials how to do so) Here is what you get:

3- Duplicate the layer with your extracted object (Ctrl+J) and rename it "Shadow"

4- With the "Shadow" Layer selected, press Ctrl+T to transform it. To transform the layer properly Hold the Ctrl key down and Click annd Drag the handles to distort it. Try to Follow the lighting of the object and the perspective. Here is my result. DO NOT Confirm yet.

the circles mark where the transformation needs adjustments. Try to match the feet. Move the extracted object layer on top of the "Shadow" Layer.


5- With the "Shadow" Layer selected, go to Image >> Adjustments >> Hue/Saturation. Set the lightness to -100, so that the layer is completely black. Set the opacity to 55%

6- With the same layer selected go to Filter >> Blur >> Gaussian Blur, and set the radius to 15px.

That's It, you now have a real life shadow with your character.

Hope you enjoyed it.
JayX