Brainstorm topic ideas with your students. Ask each student to think of a time when she became upset because someone disagreed with her or didn't want to listen to her opinion. The key to getting students to write persuasively is to inspire them. Find inspiration in topics that your students know and are passionate about. Brainstorming is one way to get students talking and reflecting about potential topics.
Assign a research project before you even begin talking about writing an essay. After each student has chosen a topic that he is passionate about, ask him to find support in the form of scholarly articles or other appropriate sources of information from experts that he could have used when trying to prove that he was right to someone who didn't share his beliefs.
Determine the audience that you want your students to write persuasively to. If this is a class assignment, as the instructor, you will probably be the audience. But you may choose to ask each student to pretend she is writing to someone who disagrees with her opinion. Emphasize the importance of respecting your audience, understanding the audience's needs and opinions and figuring out ways to make your audience trust you.
Communicate with students about the importance of organizing information appropriately to help the audience understand the information. Help each student create a thesis statement that summarizes his main argument. Then, tell each student to organize the main arguments that support his thesis into evidence paragraphs that can be used to prove his point.
Emphasize the importance of never wavering from your position during a persuasive essay. Remind each student that although she should incorporate opposing viewpoints, she must also rebut these ideas with evidence to support her own argument. Tell students to stick to facts instead of relying on opinions, as facts are more likely to sway the opinions of the audience.