Consider Sun Angles and Time of Day

The time of day can be important depending on the orientation of the building. (Advice based on Northern Hemisphere conditions) If the main entrance is facing East – a morning rendering will have the most sunlight. If the building is facing South – then you will have the most latitude when you choose your time of day. If the building is facing West – then an evening rendering will give you the best daylight. And if the building is facing North – then you're screwed! 

A building with the primary entrance on the North side, i.e. – always backlit by the sun is the most difficult exterior shot to take. Consider rendering on an overcast day, in the morning or in the evening. 

Rendering in the morning or evening is the best way to ensure the shot will be within the stop range of the camera. A rendering of the South face is probably the easiest because everything is washed with sunlight so anytime of day usually works.

The other thing to consider is where shadows of neighboring buildings fall during the day. If the building is in an urban setting, there might be a small window of opportunity when the sun shines directly on the building depending on how narrow the streets are.