Take a stance on an issue. Your position on this issue should be clearly stated in your thesis statement. The thesis statement contains your position plus your reasons. For example:
The designated drinking age should be changed from 21 to 25 because adolescent youths are involved in more accidents and frequently engage in high-risk behavior while driving.
Find valid sources that support your argument. You want to seek out scholarly sources. Websites are permissible if they are scholarly and reliable, such as those that end in .edu or .gov. Search for articles from online academic journals, such as JSTOR, Project Muse or ProQuest.
Draft your paper and list your major points. Your draft should state your arguments clearly in the topic sentences of each paragraph. Add quotes from secondary sources to strengthen your paper. Additionally, you should address reasons someone might have against your argument. That way you cover both sides while still asserting your own position on an issue.
Make sure your paragraphs are well developed and include your analysis in the section. Developed sections for an argumentative paper include at least three supporting reasons for each section. Your evidence must be followed by an explanation. Evidence comes by way of quotes, statistics or interviews. Anytime you quote from a source, you must follow up with your analysis. Answer the question: "And that means what?"
End your paper with a strong conclusion. Reassert your position on the issue you're writing about, and then include a call to action, issue a warning, add a quote or circle back to the beginning. Remember that your conclusion is your last chance to convince a reader that your stance on an issue is correct. Keep in mind, however, that this does not mean that you will raise any new points.