I'd like to add a little bit to the parties of Chapters 2 & 3. The party at Myrtle's apartment, especially when juxtaposed with the parties in the proceeding & following chapters, reflects the lack of mobility among social classes. It's basically Myrtle's pathetic attempt at a "high-society" gathering, but the vivid descriptions of the apartment show the true situation. Notice the continual mention of size:
The apartment was on the top floor—a small living-room, a small dining-room, a small bedroom, and a bath. The living-room was crowded to the doors with a set of tapestried furniture entirely too large for it, so that to move about was to stumble continually over scenes of ladies swinging in the gardens of Versailles. The only picture was an over-enlarged photograph, apparently a hen sitting on a blurred rock. Looked at from a distance, however, the hen resolved itself into a bonnet, and the countenance of a stout old lady beamed down into the room.
Everything is crowded and cramped, & Nick feels the pressure later, describing trying to leave the room akin to "ropes" pulling him back. Myrtle is trying to cram aspects of upper class living into her tiny apartment, and not succeeding. Indeed, just as moving about the room is difficult, so to is moving on the socio-economic ladder.
The party in Chapter 3, as the previous poster points out, reflects the extravagant yet ultimately unfulfilling life of Gatsby. The colors, the cars, the fruits: all have been analyzed and critiqued for decades as symbols of the indulgent lifestyle. The girls giggling, seemingly interchangeable, the lights, the music...and in the midst of it all, Gatsby stands alone.
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 with Gatsby’s head for one link.
Thus he stands outside the movement and the excitement, foreshadowing that he is searching for something else. All this extravagance is not what he's aiming for. Of course, after reading, we know he's looking for Daisy, but as of now, we simply have one man alone in a crowd of his own making.
It's not completely clear to me what you mean by analyze here, so I'll just give you some general comments.
I think the purpose of the first party is to introduce the characters of Daisy, Jordan and Nick, especially. It is supposed to give us some insight into their characters -- especially those of the women.
The party in the city in Chapter 2 is meant to show us more about Tom, I believe. We are shown just how uncouth and unpleasant Myrtle Wilson's friends are. If Tom is cheating on Daisy with a woman like that, what does it say about him?
The party at Gatsby's in Chapter 3 is meant to show us the sort of life Gatsby leads. It's a really emotionally vacant life, just as the party is emotionally vacant. It's all just show and no one really cares about what is going on.
I hope that's somewhere close to what you had in mind -- more precise questions will get you better answers...