Assyria: 911-612BCE, Northern Mesopotamia

Terror tactics were used to supress resistence from conquered peoples. Also used mass deportation to acquire laborers. The empire also ruthlessly exploited the wealth and resources of their subjects. The government did not seem to distinguish between native Assyrians and deportees. They were all equally exploitable. Despite all their terrible actions, the also provided the same legal protection for all of their subjects.
The king was seen as the chosen representative of the gods. He controlled evything, even the nobles were his servents. The empire seemed to have a well-developed bureaucracy.
Based in Ashur, along with the political power. The function of religion was primarily to reinforce the legitimacy of the actions of the ruler.
Never seemed to figure out exactly how to efficiently control their massive empire (relatively speaking.) Control was weaker the farther from the center of the empire one went. They did, however, preserve the achievements of the Mesopotamians.
Possesed Iron weapons, which provided a large advantage over their bronze-weilding enemies.
Most trade occured locally. However, the state allowed for some long distance trade due to the desire for luxuries and the money from trade. Silver was the primary medium of trade.

Some interesting images:
A golden plaque created in the later period of the empire
A relief of a winged deity of some sort. Note the flower-esque ornamentation on the wrists and staff.
Yet another relief in a similar style. Again, note the ornamentation.