State your thesis in an appropriate form. Never use a question as a thesis statement. Avoid lists in your thesis statement, which are ineffective for argumentation, although they might work for informational papers.
Narrow your thesis if it is too broad, or broaden if it is too specific. Because paper lengths vary, you will need to adjust your thesis statement to the length of your particular essay. Consider the number of body paragraphs your essay will contain, and read essays of a similar length to help determine whether your thesis statement is too broad or too narrow. If your reading audience consists of specialized readers, be particularly sure to make the topic narrow enough to be relevant and convincing. If you're writing for a more general audience, avoid making the thesis overly specialized.
Convince your audience by using an appropriate tone. Never use a preachy or accusative tone in your thesis statement. For example, the thesis statement "War is wrong and should be avoided at all costs" is overly moralistic and preachy. An arguable thesis statement is more than a mere statement of opinion. Instead, phrase your thesis in a way that opens it up for rational, evidence-based discussion. As noted by Harvard University Writing Center Tutors, a confrontational thesis statement puts your readers in a defensive position and may make them less likely to consider your argument.
Clarify your thesis statement by eliminating any wordy or unnecessary language. For example, the thesis statement "Jane Austen's novels attract feminist audiences because of the strong female characters they illustrate," reword the thesis statement as "Jane Austen's strong female characters make her work relevant to the feminist movement."
Limit your thesis statement to one essential idea. A thesis that contains more than one point will not only confuse your readers, but it will also make your paper more difficult to organize and write. For example a thesis statement like "The French Revolution changed the political environment in France and made a significant impact on the future of political regimes, such as American democracy," is not only too broad for a short argumentative paper, but it also contains more than one main idea.
Take a stand in your thesis statement. A thesis statement like "The fast food movement had positive and negative effects on American eating habits" is wishy-washy and vague. Improve your thesis statement by taking a stand on the issue and expressing your position clearly and rationally, without appealing to emotion or opinion.