Some people are easier to convince in your than others. Getting friends and colleagues to make introductions for you doesn't require much persuasive effort because they know you and (presumably) like you. Therefore, they're willing to work on your behalf. Your powers of persuasion with them stem from your credibility and likeability--not from your rhetorical prowess.

A hiring manager, on the other hand, generally doesn't know you from any other candidate's resume, so you have to work harder to convince her that you're worthy of her time. In such situations, job seekers would benefit from understanding the fundamentals of persuasion. Here to explain them is James Borg, a workplace psychologist, business consultant and author of (FT Press 2009).

According to Borg, effective persuasion combines equal parts communication and observation. It hinges on having good --being able to read people, being a good listener and being empathetic.

You need to be a keen observer of the person you're trying to persuade, says Borg, so that you can match the tone and language you use in conversation to the other person's tone and language. You should watch how the other person reacts physically--through their --to what you're saying. If you notice a negative reaction, he adds, you know you need to change your tact.

To be an effective influencer, you also need to be likeable and trustworthy, says Borg. "Whether you're selling an idea or a product, people tend to buy people," he says. "If I like you, I will listen to you. If I don't like you or your message, I won't listen to you. Getting someone to listen to you is the first stage of persuasion."