Writing an essay about figurative language is easier if you organize your essay. Try this formula and fit your contents to it.
Start with an attention-getting statement about poetry or the issue in general. Next, include the author's name and title in a background statement that provides all of the necessary information to understand the question in general. Lastly, for the introduction, included in your thesis statement is your controlling idea about figurative language.
For each paragraph after the introduction, start with a topic sentence that is your mini-thesis for each paragraph. Then use evidence to support that thesis, followed by your analysis explaining the link between the evidence and your topic sentence. Then do that for each paragraph.
In your final paragraph, which is the conclusion, rather than restate what you already said, try writing either your general feelings about the poem such as a final dramatic statement or your thoughts about the poem in the general that will really add punch to the essay at the end.