I don't get the fill light of the left of the sphere.
You have to apply a highlight point to the sphere in order to give to the viewer the information of from where the light is coming.
I also have to say that the sphere looks a little bit bumpy and not as smooth as it should be. I would recommend you if you want to learn about lighting to search about the film noir lighting schemes. Also if you want I can post some of my old notes for you about lighting.
Keep trying and searching about information.