Step one in writing a persuasive essay is choosing a topic that can be argued and that you believe in. You need to be committed to persuading your readers that they should feel the same way you do about your topic before you will be able to write a strong essay. Choose a topic that has more than one side and that is relevant. If this is an assignment for a class, your selection may be narrowed by course requirements. If not, think about your potential audience and try to find a subject that will be interesting and controversial, or at least thought-provoking, for your readers.
Researching your topic will involve both finding support for the position you want to support and finding arguments or evidence against other viewpoints about the topic. Use as many different sources as you can locate in the time you have available for research. Find and use quotations that strongly explain or support the major points you wish to use to persuade your readers that your position is the correct viewpoint. Remember, that is your goal - to bring your readers to your point of view about your topic.
If you have time, ask friends or family to read and give their reactions before you submit your final essay. If they do not agree with your position after reading the paper, ask them why. Rewrite to do a better job of explaining your position or add more support to your arguments as needed.