Adapt the format and structure your argument to fit what you need to say about the text.

The theme will be the focus of the analysis.

Like the essay itself, the thesis can be either simplistic or sophisticated. It is important to remember that the thesis statement controls the entire composition. If an idea is not stated in the thesis—either directly or indirectly—then it does not belong in that essay. A focused and concise thesis statement will give you a greater chance of producing writing that clearly communicates your argument.

A formula for the most basic analysis thesis could look something like this:
In (title of poem/novel/play), (author's name) uses (1st literary device), (2nd literary device), and (3rd literary device) to (show/criticize/explain/etc.) (some aspect of human nature).

Notice that the second part of such a thesis (beginning with "to") identifies the theme of the passage, which will be the focus of the analysis. An example of this type of simple thesis is:
In "If you Were Coming in the Fall," Emily Dickinson uses simile, diction, and syntax to describe how people wait, hoping to fall in love.

If all you do in one body paragraph is give a few examples of irony from the text and simply identify them as irony, then you haven't analyzed anything. The analysis part involves explaining how those examples are irony and how they help to communicate the theme of the passage. But to be sophisticated in your analysis, you must have ideas that are "in-depth" - not just the superficial facts of what you see on the page. You must interpret what the author has given you to work with and show that you understand the theme.

This is where your composition and analytical skills intertwine: the words you use to express your ideas and how you structure your sentences go a long way toward achieving that goal of "sophistication." A well-crafted composition will make the reader understand clearly the relationships between the ideas; it will give the reader food for thought without making the task of understanding your ideas so difficult that reading your essay becomes a challenge.