HI Vera
Straight off, I would always recommend that you change the light scale from the default scalar to Watts, which allow you to balance your lighting using real world values.
So in your case changing the Scalar value of 80000 on the spots to 100W (for the exhibition spaces) immediately makes things look a bit more realistic with more balance in light and shadow.
The emissive material on the globe lights needs to be set to 50 or some such or choose a different lighting method like,a sphere light or turn each globe into a mesh light, this will give you much more control over the effect and appearance of these fittings as you can separate the light from the material, so as these are likely to be frosted / translucent glass you can Geta more realistic look for these pieces.
I see you have set the main lighting from the Sun and Simple portal lights in the windows.
Its worth using a Dome light with an HDRI image for general scene lighting (its also very efficient as Vray offers adaptive Dome lights now so you don’t have to put portals in the windows.
Yau also have to think like a photographer and consider fill lights and secondary lighting, particularly in parts of the scene that don’t receive any environmental lighting.
So in you set scene, you might want to place some fill light in the exhibition space to spill into the cafe area.
Its also worth downloading IES profiles for spots, this will give you actual cone and penumbra values of real world lights. IES files are usually free from manufacturers websites.
Change your camera settings for now to Auto and let Vray take care of exposure and white balance until you are ready to tackle that.
Its also about artistic intent - so I assume you are going for an early morning feel.
Try out your lighting setup on a clay render (material override) to get the basic setup then you can got about introducing materials and tweaking lighting based on the results
Heres a very quick clay render after a bit of application off the above…
