First off, watch some tutorials for exterior lighting for vray. There are a couple of nice ones around here which will pretty much teach you everything you need to know.
But yes the points above are absolutely valid. It seems you are using no GI at all, just direct lighting. No way that is going to look realistic. Try using either a nighttime HDRI or a dark blueish domelight light like was suggested above. This should take care of the ambient /fill lighting. Now the rest of the lights. You should use IES lights for specific lights like spotlights. Cause even spotlights arent perfectly round. Also get rid of the trees/bushes & the person, they make it look cheap. Also, it's better to actually model a background than to use an image for it, cause this is going to look pasted in most of the time.
Again watch some exterior vray tutorials. That'll teach you to make it realistic instead of being rendered in sketchup