An argumentative essay is your opportunity to present and support your opinion about a topic.
In choosing your topic, pick a subject about which you have a definite opinion. Make sure it is a topic that is open to argument, not too broad and something about which your audience will care.
To support your argument, you will want to gather evidence or illustrations that validate your judgement about your topic. Use credible sources for your information and try for a variety of types of support for your position. Use statistical data, use authoritative commentary, use your own personal experience and/or knowledge if it is applicable.
After presenting your argument and the supportive details you have found, you may want to explore the consequences of your position. How does this situation impact another situation? Why is it important to be aware of this situation? If you can dig a little deeper into the ways in which your position might affect other positions or people, that could add to the credibility of your essay.