Three things that are proven that Mesopotamia was advanced was that they made the first writing system, they invented the wheel, and irrigation systems. They invented a variety of cities, also. Mesopotamian people were the first to create a specific type of writing, also known as cuneiform.
Writing system/ The Sumerians were the ones who created the first system of writing. They did this by using clay tablets and they carved things into they clay with a wooden like stick.
The Wheel/ The Sumerians used the wheel for wagons, transportation, ect. The wheel came in handy for the Sumerians. It made the early life easier.
Irrigation/ They used irrigation systems to control water supply. They did this so all plants would get the same amount of water. No more, no less.