He means increase the Final Gathering accuracy. If you have to increase it too much and it's killing your render times, you could decrease it and set the Filter to 1 as a start to get rid of the speckles.

The scale seems off, I think its the toilet, it looks huge in comparison to everything else.

There are some things going on that's stopping it from being realistic and it mostly concerns the shaders:

1. The metal/mirror as ND said. I don't know what its reflecting, too many mysterious white spots and others have razor sharp reflections. The shelf shader is a bit ambiguous, is it plastic, is it wood, I don't know.

2. The glass is very clear, almost surreal. Do you have it set to be 100% transparent?

3. Are the shaders gamma corrected?