There are indeed a number of similarities between the ancient Mesopotamian and Harappan civilizations. Much more is known about the Mesopotamian civilizations than Harappa as the former left decipherable textual histories. All we know about the Harappan people must therefore come solely from archaeological interpretations.
Both civilizations relied heavily on rivers. They used rivers for transportation as well as irrigation. Having a relatively reliable source of water meant that they were able to support large-scale agriculture that allowed them to feed a large population. In order to best make use of the available water, both civilizations developed irrigation and water storage techniques and technology.
Agriculture requires complex divisions of labor. Both the Mesopotamians and the Harappans had a large farmer class which was responsible for growing the food to feed centralized urban populations. City dwellers, free from the burden of growing food, were employed as merchants and artisans. This gave rise to trade, manufacturing, and commerce. Indeed, the Mesopotamians and the Harappans even engaged in trade with each other.
There is some evidence to suggest that early in these civilizations' history, women were relatively empowered for the ancient world. In Mesopotamia, written records indicate that women could make their own business and trade contracts and own property. The large number of shrines to female deities in the Indus River Valley suggests that women there had a certain degree of independence as well.
Both civilizations were ruled by a king who also likely had a religious function. The king made laws, conducted treaties, headed the bureaucracy, led the military, and settled disputes.