Answer:
By creating a strict written law to be followed
Dividing their territory into smaller city states
Step-by-step explanation:
Rather than having one central government taking care of all regions, Mesopotamian government separated their region into smaller city states.
These city states have their own leader and the leader have the authority to create decisions to manage its own territory. This took off a lot of workload from the central government.
On top of that, Mesopotamia enacted a written law that must be followed by all the people in the region. So even though each city states have different local government program, the people still abide to the same higher law.