These sure feel like those school essay I used to have to do. Brings back memories, especially about Gatsby. Yeah, we had to study the book in detail, so I sure do get what you mean. I can't really comment on these essays anymore as it's been quite a while, but I'll say a bit.

You've integrated the quotes, which was the good part. The part you're sort of missing is to integrate the explanation. Instead of saying 'this part' and then saying 'this shows', you're better off putting them together. E.g. You'd state what it is, and during your explanation include the quote and how it effected it. You've sort of broken it up a little. It's getting there, but it's as though it's too obvious that you're trying to break it up into parts and explain each bit.

I'd also reinforce a bit more in the conclusion. Wrap it up a bit better.