Fact is, nearly everything you write to someone else is persuasive to some degree.   A research paper tries to persuade readers to believe what it explains by careful explanation and evidence.  A story or essay may try to persuade readers to identify with its characters or to experience second-hand the events described.  A letter home from college might try to persuade mom or dad to send more money.

Whether or not the author acheives her persuasive purpose is an entirely different story.   

When you really want to be persuasive, you need to truly concentrate on your purpose and your audience's needs--what do they need to know, to understand, to feel, and to do? 

Of course, every audience and every individual is different.  You can't always write the perfect paper for everyone.  Your job is to simply do your best at anticipating the needs of your readers and craft your paper as well as possible.  The points that you will learn from the persuasive paper, if you follow the instructions carefully, will help you to overcome any obstacles and to write effectively.