The Thought-Provoking First Sentence
Whether you are writing a response to Emily Bronte's "Wuthering Heights," a personal reflection essay, or an essay explaining the importance of a particular economic theory, the introduction is the anchor of the rest of the essay. The first sentence should be what is called a "hook," or an exciting and thought-provoking idea. If your essay about "Wuthering Heights" will explain the concept of wild nature as seen through Heathcliff's characterization, your first sentence might contain your visceral impression of the landscape and lead into a sentence quoting Bronte's early description of the wild Heathcliff.
Providing Support for the First Sentence
The thought-provoking hook in the first sentence should be followed with a sentence that moves the hook toward the thesis. The second sentence must interpret the thought-provoking first sentence and make it relevant to the thesis. If you are writing a personal essay on time management in a mother's life, for example, you would begin with an exciting hook showing the baby crying, the PTA calling, and a row of school lunches to be made, and then you would transition into the second sentence of the essay: "Clearly, no one can manage all of these tasks simultaneously."
Transitioning to the Thesis
By sentence three, you are ready to state the problem your paper is going to tackle. You take the hook and its interpretive second sentence and move toward the thesis by adding a sentence that does not yet state the thesis but introduces the problem or issue that you will address in the paper. The previous example of time management in a mother's life should be stated as a problem or issue that you the writer will explain how to solve through the essay. For example, a third sentence might state that a time-management strategy is essential for busy mothers.
Arriving at the Thesis
Now that you have the hook, the interpretation, and the transition to the issue or problem that is addressed in the paper, it is time to write the thesis. If the thesis is about time-management strategies for mothers, you will set forth a claim about a particular time-management strategy or strategies that you will explain in the paper. The thesis is often part of the "data-claim-warrant" or Toulmin model, which provides evidence about a problem (data), declares a solution (claim/thesis) and then shows how the evidence in the paper supports the claim (warrant). This is a common strategy in higher-level essays.