First of all, a couple of points about your settings:
- You don't need to have such high intensity settings for your Primary and Secondary bounce (Intensity) figures in the GI rollout.
Basically, try to keep them between 95-105 or 110% at the most, and instead control the brightness using the Physical camera ISO number (use higher numbers if the image gets too dark).
Using the high figures you're using is not just unrealistic from the point of perspective of how light works (remember that this is a physical engine which approximates how light should normally work), but it also throws off all your reflections and colour-bleeding and ends up giving it that plastic, unrealistic, cartoon-ey look.
- Use another way of lighting your scene other than just a flat single color background. Physical sky is fine, but personally I find it more useful to invest in good HDRI sources since they provide great variation in color and light depth that give the scene more depth and realism than just a single flat color (which you never see in reality except in a studio) or even the physical sky (which is essentially just an almost linear formula for how the sky lights up but isn't entirely accurate enough).
The HDRI's and HDRI environment setting are also great for giving good reflections on your glass and other reflective surfaces so that your scene doesn't look like it's sitting in the middle of nowhere like in some sci-fi space or something that also looks unrealistic.
- Also make sure your 'Glass optimisation' (under 'Details', I believe) is turned up to max for better glass reflections and then also make sure your glass material settings are set to give you a good reflections and refraction since that's typically half your battle in making your scene look real and good.
Also try to have better reflections on other surfaces too (softer, blurred reflections, etc. Flat reflections or no reflections at all, also don't help in giving your scene a sense of depth).
- You also don't need to have such high Ray depth and Reflection depth numbers.
They just needlessly drive up your render calculation times without really giving you any more benefit or that much more benefit and also contribute to blowing out your scene. (making it too bright).
- And in the General Options rollout, turn on 'Blurriness', turn up Ray threshold a bit, and also turn down Global brightness (you don't need it that high).
Lastly, not settings related, but still...
Get rid of the "people" figures.
They're awful and completely take one out of the scene, if realism is really what you're after.
I would go the route of using silhouettes as someone else suggested (since then it's clear that you're definitely being abstract in representing people and are only using them for scale and reference) or if not then don't use any figures at all, or add them in post-processing in Photoshop using better sources.
Other than that, it's just trial and error, and don't go overboard with the settings otherwise you're struggling trying to find what's wrong and what's not working when everything is set to max or is set too high.
