(FORTUNE Magazine) – What separates people who do well in life from people who fail or who simply never seem to get very far, despite obvious smarts and skills? In his groundbreaking 1995 bestseller, Emotional Intelligence, psychologist Daniel Goleman drew on a wealth of new research to argue persuasively that what we usually think of as intelligence--as measured by IQ--is far less important as a predictor of a person's path in life than one's supply of attributes he calls emotional intelligence: self-awareness, impulse control, persistence, confidence and self-motivation, empathy, and social deftness. Now Goleman has written a sequel, Working With Emotional Intelligence (Bantam, $25.95), that zeroes in on how these qualities, or the lack of them, can make or break your career. Goleman, who is CEO of Emotional Intelligence Services in Sudbury, Mass., recently talked with FORTUNE's Anne Fisher about why emotional intelligence is more essential now than ever--and how to tell whether your emotional intelligence could stand some improvement.

In an era that seems preoccupied with technology and technical skills, why place a premium on "soft" stuff like emotional intelligence? How important is it really?

The data that argue for taking it seriously are based on studies of tens of thousands of working people, in every kind of professional field, and the research distills precisely which qualities mark a star performer. The rules for work are changing, and we're all being judged, whether we know it or not, by a new yardstick--not just how smart we are and what technical skills we have, which employers see as givens, but increasingly by how well we handle ourselves and one another. In times of extremely rapid and unpredictable change, like right now, emotional intelligence more and more comes to determine who gets promoted and who gets passed over--or even who gets laid off and who doesn't.

This is true at every level of the organization. For instance, one study of what corporations seek when they hire MBAs shows that the three most desired capabilities are communication skills, interpersonal skills, and initiative--all elements of emotional intelligence. And the higher you go up the corporate ranks, the more these things matter.

How do you know that?

We've been able to quantify it in a couple of ways. I did one study where I gathered from HR training and development specialists their competence models--which are essentially lists of the most desired traits--for 181 jobs in 121 companies worldwide, with their combined work force numbering in the millions. Once we separated out the purely technical skills from the emotional competencies, and compared their relative importance, we found that two out of three of the abilities considered vital for success were emotional competencies like trustworthiness, adaptability, and a talent for collaboration.

That finding has been supported by other in-depth studies showing that emotional competencies are twice as important to people's success today as raw intelligence or technical know-how. And in any kind of managing or leadership position, emotional intelligence is of paramount importance. Often when you see people get promoted on the basis of technical ability and then fail in that new job, it's because they were promoted for essentially the wrong reason. They lack emotional competencies that are crucial at that higher level. More and more companies are realizing this and altering how they train and promote people accordingly.

Which emotional competency is most important to someone who has, or wants to get, a high-level executive job?

It's hard to single out one trait as most important because different aspects of emotional intelligence come into play depending on the circumstances. But one distinguishing characteristic is, how persuasive are you? Can you get "buy-in" for your ideas from the people around you? The most effective leaders have a very finely honed political awareness and ability. The word "political" is loaded, I know, because it carries negative connotations of empty charm, manipulativeness, or someone who is good at managing up but not down and is really interested only in his or her own gain. But "political" in the sense I mean is a knack for articulating a mission or a goal and knowing how to bring everyone on board to get it accomplished. Can you take the pulse of a group, understand its unspoken currents of thought and concerns, and communicate with people in terms they can understand and embrace? That is great leadership. And it takes huge social intelligence, including a strongly developed sense of empathy.

Beyond taking a quiz like the accompanying one we've devised, how can a person gauge his or her own EQ?

It's very tough to measure our own emotional intelligence, because most of us don't have a very clear sense of how we come across to other people, and that is much of what ultimately matters here. What you really need is to have someone else, or preferably a cross section of people you work with, rate you on the various components, such as trustworthiness, reliability, flexibility, how good you are in a crisis, and how open you are to new ideas and new ways of doing things. This is why 360-degree performance evaluations are so helpful. A 360, in which you are getting honest feedback from people above, below, and beside you, can give you a very clear sense of where you need to improve. The areas to focus on especially are the ones where your boss and your peers see you very differently from how you see yourself.

What about people who work for companies that don't offer 360-degree evaluations?

Clearly it will take a little more work on your part, but you can set up your own. Pick some people whose judgment you respect--including perhaps your immediate boss, a couple of peers who are neither your best buddies nor biased in any other obvious way, and maybe one or two people below you in the organization who have worked closely with you. Ask them to rate you according to the quiz, or use the more detailed list from the book. You may be very surprised by their answers, and by how much the score they give you varies from the score you give yourself. You want to be on the lookout especially for points of agreement, areas where, for instance, your boss and your subordinates all see the same shortcoming in you. Maybe nobody thinks you listen very well, or everybody more or less agrees that you tend to lose your temper pretty easily. Whatever the specific problem, that's where you need to direct your attention.

Let's suppose I give myself a high rating on, for example, being open to new ideas--yet my colleagues see me as rigid and inflexible. How do I go about fixing that?

You can do it. Emotional intelligence is not a fixed quantity, and in varying degrees we're all increasing it as we go through life. To change a particular tendency, what you need at the outset is motivation. You have to want to do it, not just because someone tells you that you should, but because you see the importance of it. Most shortcomings in emotional intelligence are the result of habits of mind that are deeply rooted because they are learned very early in life. For example, a reluctance to consider new ideas may come from some experience in your childhood that taught you that new ideas are too dangerous or risky, that if you go out on a limb you may fall off and get hurt.

There are two basic steps in transforming any mental habit. The first is to notice when you are falling into it. Monitor yourself. The next time someone proposes something new and you catch yourself automatically thinking "No," stop and think. Jot down some notes, if that helps you. Why does this particular idea make you uncomfortable? What's the context of the discussion? What are the emotions that go along with resisting the idea? Do you feel threatened by it in some way? Why? Don't judge yourself or tear yourself down. Just try to analyze your own reaction to the situation.

What's the second step?

Practice a different response. This will feel strange at first, and it is a real effort, because you are dismantling an old habit and building a new one. You might even deliberately set up a situation where a lot of new ideas will be thrown at you--for instance, call a meeting with the express purpose of getting your team to brainstorm about different ways of doing things. Then concentrate on keeping your mind open to what people suggest. It does take time for new mental habits to form. It doesn't happen instantly. But by being aware, you can do a little better each time you try.

It helps to have some support. Many executives hire a coach to help them alter a specific behavior. A more practical approach for most people is to find a role model in your own workplace, a colleague who is especially strong in a trait you'd like to develop, and emulate that person. Watch how he or she handles a given situation and see how closely you can adapt your own style. As you feel you're getting better at the competency you're trying to develop, ask the people around you for feedback. You might even encourage a colleague to give you a signal when he or she sees you slipping back into your old habit.

Should companies be developing formal training programs to help people strengthen emotional competencies?

Lots of them are already doing so, yet it is such a complicated task that right at this moment millions and millions of dollars are being wasted on programs that have no lasting impact, or little effect at all, on building emotional competence. It amounts to a billion-dollar mistake.

Heads of development at plenty of FORTUNE 500 companies know this, but the ones who wanted to have their own programs have been frustrated because they lacked standards and yardsticks for training in "soft" skills. That's why I co-founded the Consortium for Research on Emotional Intelligence in Organizations. It's a coalition of researchers and practitioners from business schools, consulting firms, corporations, and the federal government. We've come up with basic guidelines for the best practices in teaching emotional competencies, and these are described in my book. If it's done right, this kind of training yields remarkable results.

Can you give us an example?

Sure. The Weatherhead School of Management at Case Western Reserve University has developed an innovative course called Managerial Assessment and Development that incorporates most of the consortium guidelines. Since 1990 this course has been offered to several groups of students, mostly men and women in their 20s and 30s pursuing an MBA after several years on the job. Each student starts the course by choosing a specific set of competencies he or she wants to strengthen. Instead of the familiar one-size-fits-all approach to management training, students construct a highly individualized learning plan. The class then meets for three one-hour sessions a week over nine weeks.

To gauge how well it works, Weatherhead has put its students through a set of rigorous assessments, using measures of applied emotional intelligence that the consortium gleaned from corporate employers. When the ratings are compared with the assessment scores the students earn when they start the program, they show an average 86% improvement. And even more significantly, follow-ups three years later have consistently shown these gains holding on the job. So based on results like this, it's clear that, if they're given the right tools, people can master the emotional-intelligence capabilities the working world demands.