Think of the times when you've bought something that you wanted but didn't necessarily need.
Your world is full of examples of successful marketing, so keep your eyes and ears open. Start reading those long sales letters in magazines and newspapers, and on the web. Read the sales letters you get in the post. Listen to radio ads and watch ads on TV.
Become aware of how you are sold things and more importantly, how you buy things.
If you see a marketing technique that works for you, it probably works for other people too!