One-on-one meetings with industry insiders are a great way to get insights that can help you land a job. Just one question is off-limits.

FORTUNE -- Dear Annie: I'm trying to change careers, hoping to apply my two decades of consumer-product marketing and branding experience to the health care field. I'm at the point where I'd like to set up some one-on-one meetings with networking contacts who are senior managers at health care companies, partly to see where they think my qualifications would fit in the industry, so I can focus my job hunt accordingly.

These are very busy people, so I want to make the most of whatever time they can give me. Coincidentally, my daughter, who is graduating this spring and wants to go into finance, is doing informational interviews with people in that field (on the advice of a career counselor at her college). We've come up with a short list of questions, but do you or your readers have any suggestions? Is there anything to avoid asking? -- Dallas Dad

Dear D.D.: Interesting question. Since your goal in an informational interview is to find out as much as you can about your chosen field, the more you already know about it, the better. "So be sure to research both the latest developments in the industry and the background of the person you're meeting," says Paul Freiberger, a former McKinsey consultant who now runs a career coaching firm called Shimmering Resumes and the author of When Can You Start?: How to Ace the Interview and Win the Job.

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"Keep your questions open-ended," he adds. "Questions that can be answered with a simple yes or no are dead ends. In order to gain any real insight from it, you want the interview to expand into a working conversation between two people with shared interests. Open-ended questions push things in that direction."

Naturally, what you ask depends on what interests you most and will vary with each of your interviewees, but Freiberger suggests these queries as possible starting points:

• Where do you see this industry (or profession) going in the next few years? What changes have you seen in the course of your career so far?
• What specialized training or education is required to succeed in this field now? How has that changed?
• Which skills have you found most helpful, and which ones will be most important in the future?
• Could you describe your average workday and your key job responsibilities?
• What are the best and worst things about working in this field today?
• What resources help you keep up with the industry? Which trade or professional associations have you found most useful?
• Has anything surprised you over the course of your career? What changes have you found most challenging?
• Would you choose this field if you had it to do over again? Is there anything you would do differently?
• What are the biggest technological changes influencing this business right now?
• In what ways does your job affect your life outside work? How do you see work-life balance issues affecting colleagues?

"Don't hesitate to ask about things that are specific to your employment situation," says Freiberger. "It's fair game to ask how your existing skills and experience or education fit into the field, and how you can improve your prospects going forward." He recommends bringing your resume to the meeting: "You're not going to thrust it into this person's hand, but you want to have it available if he or she asks to see it."

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Since most informational interviews are short -- often just 15 or 20 minutes -- it's smart to lead with what's most relevant to your job search. Freiberger suggests bringing a list of questions in descending order of importance. As for what to avoid asking, he says, "Aside from questions that are ridiculously inappropriate ... there is only one absolute taboo: Don't ask for a job." If all goes well, that will come later.

Talkback: What questions have you found most useful in an informational interview? Leave a comment below.