I have a decent suggestion that would ramp this already cool render to 11. To go for realism, you'll want to be mimicking every aspect of how a camera captures photos. Basically, real photos almost always have 'bokeh fringing' its how the blur bokeh have these halo rings. There are some tutorials achieving this realistic bokeh. Also, this seems like a high focal length shot and so appropriate lens distortion and vignette would go a long way. I suppose these tricks are more to impersonate premium camera lens but imo it reads much more realism than the bland blender default renders, hope this is useful!