The ability to persuade others is a valuable skill. It can translate into making a huge sale, convincing people to follow your leadership, getting a raise, or countless other successes in the business realm. In your personal life, it can mean winning over a partner, well-behaved children who do as they're told, and friends and family members who will help in a pinch. But persuasion isn't just for charismatic types--anyone can be better at getting people to say yes to requests. Take it from Jephtha Tausig-Edwards, a clinical psychologist practicing in New York and Massachusetts, who says science has uncovered a wealth of data on the subject. Here's her advice, according to what researchers studying persuasion have found.

1. Use a personal note.

Research conducted at Sam Houston State University in Huntsville, Texas, found that study participants asked to complete a survey were significantly more likely to do so if the survey included a Post-it note with a handwritten message asking for their help, akin to a favor. "This speaks to the importance of the personal touch," Tausig-Edwards says. "A handwritten note is important, especially in the current era where so much communication tends to be electronic."

2. Be up front with your request.

Researchers who published in the Journal of Experimental Social Psychology found that a request was more likely to be granted if it was asked for in the beginning of a conversation, as opposed to the end of it. "Lead with the request as opposed to saving it for the very end ... of an interaction [when] someone might be tired or they may have a competing demand on their attention," Tausig-Edwards suggests.

3. Use guilt to your advantage.

According to research conducted at Stanford University, people feel uncomfortable repeatedly denying the same person. "If someone declines a request, and then you approach them later with a different request, they are more likely to agree to your request, possibly because of some feelings of guilt or feeling that they let you down the first time," she says.

4. Use the right words.

Researchers in the United Kingdom found that language matters when it comes to making requests. So if someone initially says no or "I'm not interested," follow up by asking, "But would you consider XYZ?" or "Would you be willing to try XYZ?" This kind of language increases the likelihood that the person will answer positively. "If you're talking about somebody's willingness to do or try something, you're now focusing on their character as a person, as opposed to their preferences," she says.

5. Focus on what the other person will gain.

German researchers have found that people are more willing to agree to something if you frame your request in a manner that highlights what they will receive. "Rather than saying, 'I would like you to pay me X for something,' it's better to say, 'I'll give it to you for X' or 'I could let you have it for such and such a price,'" Tausig-Edwards says. "I think that's always important in a negotiation, so it's not 'heads I win, tails you lose' but everyone feels they've profited in some manner."

6. Remind the person he or she can always say no.

When you preface a request this way, the chances you'll get a positive answer dramatically increase, researchers in France have discovered. "[It is] reminding them that they're not hostage and that this is not a pressured situation," she says.

7. Appropriate physical touch may help.

A handshake or touch to the shoulder has been found to increase the chances that a request will be granted. Be careful with this one, however. "You definitely have to know your audience," she says. "In certain cultures and religions, [there are] prohibitions against contact let's say between opposite sexes."