Hard to say much since I dont know what your settings for materials and lights are.
But normaly if I'd do a picture like those I'd use a directlight (now a days I use vraysun ...) onley or just a HDRI (HDRI f I want lotts of reflections and I have time to sitt around for the lonng renders) not both.
And if I whas you I'd skipp the Vray sphere. Better to fill out with more enviroment light instead or a Vray plane in each window if it's to dark inside.
Decent Vray glas mat settings = refract/reflect colour pure withe IOR just below 1,6 and ad some map to the difuse like streaks or somthin
Thats about what I can say right now not knowing what your aming at.'
Edit* I also see allot of tiling textures try to use seamless and if I where you I'd look into Vray displacement for the grass, and I'm not sure about the HDR your using. Btw there is a great tutorial on the net about Vray archi and HDR renderings check it out.
