According to a survey by Office Team, an administrative staffing company, 21 percent of hiring managers have changed their minds about hiring after checking a candidate's references. To make sure your references help you nail the job, you need to pick the right people early in your job hunt, says Linda Sloan, director, Industry Relations and Career Management for the University of St. Thomas.

Key criteria for your references, says Sloan: They should be able to "speak enthusiastically from first-hand experience" about your character, qualifications and accomplishments. They should also be credible sources in their field.

Given the job market over the last few years, many job hunters' managers or supervisors may also have been laid off. Sloan says those people can still be credible references if they've moved on or even are out of work, if they are still well-respected and if they have a positive attitude. "Bitter people don't make good references," Sloan says.

Get permission

You will of course need to get permission from your references to give out their names and phone numbers. Sloan says you also need to prep your references for their role. "Don't give them specific talking points," she warns. "If it sounds like the reference is reading from talking points or a canned script, or if all your references say the same thing, you'll lose credibility."

Try to meet in advance with each person you use as a reference, Sloan says. Give them information about the position or positions you're applying for. Go over your résumé and talk to them about what you bring to the table.

Sloan advises that you ask a couple of questions to hear what the reference will say about you. "Ask yourself, `Is this person going to sell me?'" Sloan says. "Can they make me sound like a superstar?"

If you don't get the response you want, you might want to consider securing another reference - although you don't have to tell them so.

Keep them posted

Follow up with a thank you note, and then be sure to keep them posted on your job-hunting process. Give them a heads-up when they're about to get a call, and provide them with the name of the person who will be calling. Follow up again to let them know how things turned out.

As the Office Team survey demonstrates, picking people who know what you've done and can speak to your strengths can be a deal-maker.