I will assume that the glass in this image are the orange items in the middle of the frame. The lighting in this image is rather harsh and gives rise to several shadows which are very distracting.
the ligthing makes it look a bit flat. some extra contrast may have helped though especially to darken the mottled grey background. and a less straightforward composition.
Great concept, glass grapes with the real. Looks like you had the lighting under control, however, I think you may have missed your mark on the focus. Either that, or ever-so-slight motion blur.