Choose a very strong topic that has a clear, arguable side. Obviously, you cannot argue that the sky is blue. Also, look for a topic that has not been argued to death, like the death penalty or abortion.
Decide which side you plan to argue. You have to stick to that side in writing the thesis and the entire essay.
Remember that an argument essay should be somewhat persuasive. You are trying to prove the significance of a specific side of an issue.
Make a list of points to argue. An argument could go on forever, so it is essential to choose just a few strong points to argue. Consider why you want to argue this specific side – this will help you make the list.
Write a one-sentence summary of your subject, your side and the points that you plan to argue. This is a rough draft of your thesis. It must contain all three of these things and be only one sentence. For example, Toyotas are the best cars because they get good gas mileage and have few maintenance issues.
Read over your draft. Is your subject or topic clear? Is it clear that the essay will argue a specific point? Have you listed clear points that you will argue to ultimately prove your specific side?
Be sure that the thesis does not make an announcement: This essay will discuss cars.
Use very clear, direct and specific language. State exactly what the essay will discuss.
Revise the thesis using the criteria above.
Use the thesis to make an outline and write your essay.