What are the steps to writing a persusive letter?

To write a persuasive letter/ writing, you need to convince the person. TV adds persuade you to buy things. For example, " The new Toyota of 2011! More advanced and cooler! It's on sale too! Offer ends May 24th 2011! Get it now!". See, it makes you want to buy it. But you NEVER should say something negative about it. All positive. Good Luck!