(MoneyWatch) Is your lack of negotiating skill preventing you from getting a raise or being assigned the best projects at work? Negotiating may come more naturally to certain people, but anyone can improve their technique. A new book by Harvard lecturer and McKinsey Leadership Development advisor Erica Ariel Fox, “Winning From Within,” talks about how crucial negotiation is — and how the best negotiations start with the self because, in short, you will be more focused on what you want and how to achieve it. Recently, I spoke to Fox about her life’s work and her best tips for negotiating well. Here’s what she had to say:

MoneyWatch: Why is negotiation so fundamental for career success, besides getting a raise?

Erica Ariel Fox: You might think negotiation happens when you ask for a raise, or interview for a job. But actually, you negotiate all day long, with everyone you meet. With colleagues, clients, and new potential customers. With your direct reports, your boss, your partners. You make agreements and resolve conflicts with all of the people who impact the results you get.

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MW: What is the single most important thing you have learned over your career, regarding negotiation?

EF: The most important thing I’ve learned in 20 years of teaching negotiation at Harvard Law School and advising clients around the world is the crucial role played by the inner negotiation that happens inside of all of us. The most important negotiation in your life is “getting to yes” with yourself. When you learn to do that, you start winning at everything else.

MW: What part do “inner negotiators” play in this process?

EF: At first, the idea of “negotiating with yourself” sounds strange. But once you think about it, you realize you’re no stranger to the internal tug-of war. Should you stay at the office and finish your report, or keep your promise to get home in time for dinner with your kids? Part of you says you should quit your lousy job, while another side begs you to focus on the mortgage. I call these different sides of us “inner negotiators,” because this internal process mirrors what happens between different people when they negotiate. It turns out that best practices for negotiating well apply equally to the negotiation within — when you need to reach consensus among the inner negotiators inside of you in order to move forward.

MW: What do you think will surprise people about this book?

EF: “Winning From Within” does two things at the same time. It shares timeless wisdom, while also giving highly practical advice for improving your leadership and your life. You might be pleasantly surprised at the concrete tools you can use tomorrow at work and at home to put these insights into practice. People who know me will be surprised that I shared so many real examples from my life.

MW: How else does your book stand out from the pack of other similar reads?

EF: “Winning From Within” is unique in the way it integrates profound insights about the deeper dimensions of life in the context of high performance at work. And it’s fun to read. I wrote the book in a personal voice, sharing stories about my marriage, my challenges in counseling clients, and my real ups and downs over the years. So the book has lots of ideas, but it’s presented in a humorous, honest, and very personable style.