have to write a persuasive essay

Whether for school, persuading your mom to let you have a dog, or persuading your boss for that extra raise, everyone needs and should know how to write a persuasive essay. It's actually not as difficult as it seems.
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Steps
Give yourself time. Trying to cram an entire 5 paragraph persuasive essay within 20 minutes is not a good idea. Allow yourself enough time to brainstorm, write, and proofread.
Brainstorm. Writing a persuasive essay is very much like writing an ordinary paper. Of course, before you begin, you have to come up with a good solid view, a foundation which you can base your entire paper on. It's best if you pick a topic which you strongly believe in. That way, you can defend your ideas better and make your paper sound a lot more convincing.
Start off your essay by stating your views. Don't get too specific. Leave the details for later. Just lay out your main idea and opinion.
Make body paragraphs. At minimum, write four paragraphs for the body of the essay. Each paragraph should cover a main point to back up your argument and idea. Each paragraph should include three smaller points defending each larger point. If this sounds confusing just look at the diagram: 
First sentence, Main point: Cats are easy to look after.
Second sentence, Minor point 1: They are very independent.
Third Sentence, Minor point 2: Cats are very clean and hygienic.
Fourth Sentence, Minor point 3: Cats are very intelligent.
Your last sentence should be a transition to the next paragraph to help keep reading smooth.
Finish off with a conclusion (last sentence). Restate each of your points and end the whole paper with a very well written sentence that leaves the reader with an imprint of the essay. Make it something that they won't easily forget.
Proofread. Use the spell checker on your computer to check the spellings words (if applicable). Also check your paper twice for yourself to make sure the content makes sense. Have others check your paper. The more the essay is checked, the easier it is to find mistakes.


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Tips
Make sure you know your audience. Stick to a certain tone, whether it's formal, informal, funny, pleading, etc.
Be aware of the possible counter-arguments that would go against what you are trying to say. Only address these points in your essay if you have good ways to respond to them.
Avoid the use of personal pronouns such as "I" or "you". This takes away from your writing's professional touch.
Use synonyms. Having the same word over and over will place a toll on the reader's nerves. Mix it up a bit.
When restating, do not duplicate any sentence. Your audience will not skip over any part, so there isn't a need for stressing the same point over and over.
Make each sentence count. Adding extra sentences will not drive your point home. Keep the essay clear by keeping it concise.