Hi
Lighting , reflections and noise.
Lighting - Look at the lighting direction and try and match that on the robot. Particularly around the kettle edges.
Reflections - The ground and the robot would both show as reflections in the kettle (and vice versa - the joys of polished surfaces). You could paint those in, but don't overdo it.
Noise & sharpness - The rest of the scene has an element of noise and level of sharpness that is not matched in the kettle - the kettle is comparatively noise free and much sharper than the scene. It needs some slight blur and some noise/grain added.
Have fun
Dave