You might like to focus on the following points in response to this question. Clearly this chapter tells us a lot about Gatsby's lifestyle and how it is an obvious example of "conspicuous consumption." Consider his cars, and the very showiness of his vehicles, which were of course designed to impress Daisy, but ironically play a crucial part in his downfall as they are easily recognised and thus allow Gatsby to be tracked down.
Another key thing to realise is that it is strongly implied that Gatsby's wealth is derived from the illicit sale of alcohol. Note how the owl-eyed man appreciates the library, but he sees it through a drunken haze. This has occurred in spite of Prohibition and the restrictions on sale and consumption of alcohol.
The theme of pretension and reality is highlighted by the "majestic hand" with which Gatsby signs his invitations, showing that in the artificial world of his parties, Gatsby imagines himself to be like a medieval Monarch. Yet his guests conduct themselves "according to the rules of behaviour associated with an amusement park." These people form a social elite, yet their behaviour is characterised in terms of vulgarity.
Also key to think of is how Gatsby is both a part of and yet separate to this group. As Mr. Tolstoff's composition is played to the assembled crowd, Nick looks over and sees him:
...just as it began my eyes fell on Gatsby, standing alone on the marble steps and looking from one group to another with approving eyes... When the "Jazz History of the World" was over, girls were putting their heads on men's shoulders in a puppyish, convivial way, girls were swooning backward playfully into men's arms, even into groups, knowing that some one would arrest their falls - but no one swooned backward on Gatsby, and no French bob touched Gatsby's shoulder, and no singing quartets were formed for Gatsby's head for one link.
This sets up an essential paradox - Gatsby is shown to be a fundamental part of the "Jazz Age" world depicted in this book, and yet he is seen to be essentially separate from it as well, indicating some central conflict or ambiguity in his character that the rest of the novel will unfold.