Some of the Mayand and Aztects differences are: The Aztecs lived under one supreme ruler, while the Mayans had their territory divided in city estates and they each had a sovereign ruler.
Another difference is, while the Mayans had a very scientific temperament (they studied stars and developed a very specific calendar), the Aztecs were driven by war, defying neighbors and forcing them to pay tribute.
The Aztecs were believers of human sacrifice, while the Mayans were against it and offered blood instead.
The Mayans art was representing contemporary life in murals, while the Aztecs art was focused on sculptures as they were skilled craftsmen.