What are examples of class structure in The Great Gatsby?

Social class is indeed an important theme to examine in this novel, which depicts the various ways the economic prosperity of the Roaring Twenties impacts the characters.
One way to look at class structure in The Great Gatsby is by examining how F. Scott Fitzgerald uses setting to demonstrate the economic climate. In chapter one, Nick introduces us to East Egg and West Egg, two neighborhoods that represent different statuses of wealth. The citizens of East Egg belong to the established families of the aristocracy, like Tom and Daisy Buchanan, while West Egg is home to those who have only recently acquired their wealth rather than being born into it, like Gatsby. Nick describes West Egg as "the least fashionable of the two," although its residents nonetheless have a lot of money. In chapter seven, Tom speculates that the millionaires of West Egg came by their wealth through unsavory means, claiming that the neighborhood is "full of bootleggers." This provides an example of the tension between the two divisions of the rich, which plays a critical role in the book.
Another example of social class is found in the characters of George and Myrtle Wilson, who live not in either West or East Egg, but the Valley of Ashes, which Nick describes in chapter two as the home to "men who move dimly and already crumbling through the powdery air." In sharp contrast to Gatsby and the Buchanans, Myrtle and George struggle economically. In chapter two, Tom even ridicules George after George asks when a car he plans to purchase from Tom will be available, showing both his financial situation and the conflict between the rich and the poor.
The Great Gatsby has many other examples of the conflict between social classes in the novel and how this theme fuels the plot's tension. Try reviewing what you know about the characters and their environments to see what other portrayals of this topic are present.