Give, but not too much.

Noah Goldstein, Steve Martin, and Robert Cialdini are the authors of the New York Times bestselling Yes! 50 Scientifically Proven Ways to Be Persuasive. I recently met Steve on a trip to London where he runs Influence at Work, and he shared these top five ways to increase your influence and persuasion.

1. Be the first to give.

Studies show that we are persuaded more by people who have done something for us first. We give bigger tips to servers who give us a mint with the check. We’re more likely to help work colleagues with their projects if they have helped us with ours. Requests that are personalized are most persuasive of all. When researchers randomly sent out surveys, they were able to double responses if they personalized the request by placing a handwritten note on the survey.

2. Don’t offer too many choices.

Whether it’s the number of products you offer or the number of retirement plans you allow your employees to choose from, too many choices often frustrate people. Companies offering a small number of retirement plans have far greater enrollment than companies that offer a large number of plans. 

3. Argue against self-interest.

Trust is a critical component to persuasion. The surest way to be perceived as honest is to admit to a small weakness in your argument, product, or business immediately prior to communicating the strongest positive argument about your product or service.

4. Losses are more persuasive than gains.

Instead of telling your audience what they stand to gain from taking your advice buying your product, research shows that people are often more persuaded if you tell them what they stand to lose out on if they don’t take your advice or buy your product. In 2003, the Oldsmobile far exceeded its sales projections despite the company reducing its advertising and product development budgets. Why? General Motors decided to discontinue the car because of slow sales. As a result, the car became something people would be losing out on even though before the news, few people wanted one.

5. Make people feel as if they’ve already made progress toward a goal.

A car wash offering a loyalty card nearly doubled customer retention by changing their offer from “Buy eight washes, get one free” to “Buy 10 washes, get one free — and we’ll start you off crediting you for two washes.”

Some people have the ability to capture an audience’s attention, convince the undecided, and convert noncustomers into customer. Some do not, but there’s good news from social science. Persuasion is not just a skill gifted to a chosen few. It’s a science, and researchers who study it have formulated a series of rules for moving people in your direction. Learning about these rules can make you a more effective and ethical influencer. How persuasive are you? You can find out by taking the free five-minute interactive test at myyesscore.com.

Guy Kawasaki is the chief evangelist of Canva and the creator of Guy Kawasaki’s Remarkable People podcast. He is an executive fellow of the Haas School of Business (UC Berkeley), and adjunct professor of the University of New South Wales. He was the chief evangelist of Apple and a trustee of the Wikimedia Foundation. He has written Wise Guy, The Art of the Start 2.0, The Art of Social Media, Enchantment, and eleven other books. Kawasaki has a BA from Stanford University, an MBA from UCLA, and an honorary doctorate from Babson College.