A good introduction in an argumentative essay acts like a good opening statement in a trial. Just like a lawyer, a writer must present the issue at hand, give background, and put forth the main argument — all in a logical, intellectual and persuasive way.
Start With a Hook
Start your introduction with a sentence that gets the reader interested in the topic. To pique the reader’s interest, you can begin with a quote, a personal story, a surprising statistic or an interesting question. For example, if you are arguing that smoking should be banned from all public places, you can start your introduction by referencing a statistic from a verified source: “Tobacco use kills more than five million people every year — more than HIV/AIDS, tuberculosis and malaria combined, according to the World Health Organization.” This strategy grabs the reader’s attention while introducing the topic of the essay.
Include Background
Providing readers with background on the topic allows them to better understand the issue being presented. This information provides context and history that can be crucial to explaining and arguing your point. For example, if you are arguing that there should never be a military draft in the United States, your introduction can include information about the history of the U.S. draft and the events that led to it being abolished.
State Your Thesis
The thesis is the essence of an argumentative essay. In a single, clear sentence, it sums up what point you are trying to make. The thesis statement should assert a position on a particular issue — one that a reader can potentially argue against. Therefore, the thesis cannot be a fact. For example, if a professor assigns the general topic of war, you could formulate the following thesis statement: “The United Nations must be redesigned because it is currently incapable of preventing wars.” The rest of your essay serves to explain and provide evidence in support of your thesis statement.  It is essential that this thesis statement be appropriately narrowed to follow the guidelines set forth in the assignment. If the student does not master this portion of the essay, it will be quite difficult to compose an effective or persuasive essay.

What to Leave Out
A good introduction should not be describing arguments or providing analysis that belong in the body paragraphs. Your introduction should introduce and set up your point, rather than lay out evidence to support it. Also, while your intro is a road map for the rest of the essay, you shouldn’t explicitly announce what and how you will be arguing: “I am going to prove to you that …” This type of set up does not add any pertinent information and only serves as filler.