It's the question every interviewee dreads: What are your strengths and weaknesses? Interviewers love it because it helps them separate the wheat from the chaff. But for job candidates, it's the stuff of nightmares: How do you tout your strengths without coming off as an egomaniac? Worse yet, how do you admit your weaknesses without talking the company out of hiring you?

But asked in a different context—that is, outside the job interview—that question actually represents a powerful career building tool. As you contemplate your next career move, there's nothing more valuable than a clear-eyed assessment of your strengths and weaknesses. Knowing your strengths will help you market your abilities. Knowing your weaknesses enables you to come up with strategies for turning them into strengths. But first you have to identify them. Here are some guidelines:

Identify your strengths. Ask yourself what you're really good at, especially as it pertains to your current position and responsibilities. As you draw up your list, identify which of your tasks you truly enjoy doing as well as those you're skilled at but would really prefer not to do if you didn't have to. Categorize these qualities in order of skill (from those at which you are better than anyone else, to those at which you are just better than average). To help you remember all of the qualities you should consider, use your job description as a guide. You might also want to consider the qualities and characteristics listed in the job description for the position to which you hope to be promoted.

Identify your weaknesses. A good place to begin is with those tasks and responsibilities that you really dread. We often dislike doing those things at which we don't excel (particularly those of us who are perfectionists). In addition, identify those skills that you have yet to develop. Knowing that you're deficient in an area like budget projections or spreadsheet expertise is valuable information. Once you know where your deficiencies lie, you can sign up for training seminars or classes.

If you're a manager, pay particular attention to your management skills. How are your people skills? Do you consistently get the best from your staff? Just because you've been promoted to a supervisory or management position doesn't mean you know how to manage. It's all too common for companies to promote people on the basis of how well they're performing their existing job, not on how likely they are to succeed in a new job that may require entirely different skills. If that's happened to you, it's not an insurmountable obstacle. All you need to do is identify what new competencies you need to succeed at the new position and then seek out coaching or training opportunities.

One other advantage to being aware of your weaknesses is that you can hire more intelligently. As a manager, you want to hire people who complement you, whose strengths are your weaknesses. This is called full-circle management. The advantages of full-circle management are many: For one thing, it tends to reduce dissension due to clashing strengths. For another, it prevents important tasks from falling through the cracks because no one in the department is up to the job.

It is important that you be completely honest with yourself as you go through this process. This exercise is for your own information and guidance, not for anyone to use against you. Knowing exactly what you're bringing to the table in your current assignment will give you the confidence you need when it comes time for the next performance appraisal or salary negotiation. And perhaps more to the point: It will also help you position yourself for that next promotion.