How should I write a thesis for how color is used throughout The Great Gatsby?
This is for a literary analysis, and I know what colors I want to use: grey, yellow, and green, and I know what each of them mean and how they are represented; I just am not sure how to put it all together into a thesis.
It sounds like you have collected all of your examples and thought about the appropriate associations that Fitzgerald is using with the use of color in the novel. Now you need to ask yourself, why Fitzgerald uses color imagery in the novel. Is it to enhance a theme or themes? (Think about what the colors "mean"). Is it to create a more vivid realism to descriptions? If so, why is that important? Is it to drawn attention to specific details of description? It is to help create the mood or atmosphere of the scene? Your thesis statement should delineate what reason or reasons you think Fitzgerald had for using color imagery in the novel. Then your body paragraphs can go on to show/prove your thesis with an analysis of the various examples you collected from the novel.
It sounds like you have a good start. You have already decided what the colors are that you are focusing on and what each one means. The thesis should be a statement about the colors and how Fitzgerald used them in the story to tell the reader something important.
The introduction of an essay is often the hardest part to write. The thesis is meant to guide what you are going to focus on in your essay. It can be a sentence or two, and it should be clear and consise.
When I write a rough draft of an essay, I try not to get stuck on the introduction. Instead I often just write the thesis, finish the paper and then go back and refine my introduction.
Make sure that you tell the reader specifically what Fitzgerald was showing the reader. Try not to be vague. What was he trying to accomplish by using colors? What did they symbolize? If you start here, you should be able to write the paper. When you are done, you will be able to refine your thesis and introduction.