“I can’t tell you the number of times over 43 years I’ve been doing that, that I’ve had someone’s references screw the candidate’s chances to get the job,” says Anthony W. Beshara, PhD, president of Babich & Associates, a Dallas recruitment and placement firm.

Get your references interview-ready with these nine tips.

Typically, you may be asked for two or three references, but you should have a much deeper pool than that, Beshara says. Pick and choose your references depending on the type of job you’re going for, he says. Some references will be able to discuss your effectiveness in certain roles, while others may be able to discuss your leadership or team-building skills. Choose the right people to talk about the skills you need to highlight to get the job at hand, he says.

Always ask your references for permission before sending a prospective hiring manager to them, even if they’ve agreed previously, says career expert Vicky Oliver, author of 301 Smart Answers to Tough Interview Questions. Let them know who will be contacting them and whether it will be by phone or email. If you have a sense of when the hiring manager will be contacting them, that’s useful too, and helps avoid delays due to your reference being out of the office or not prioritizing a return call, because he or she doesn’t know who the hiring manager is, Beshara adds.

If you’ve got a good rapport with your references, it might be a good idea to ask them what they will say about you, says Jill Jacinto, associate director of WORKS, a career-focused media company.

That does two things: First, it gives you insight into whether the reference intends to discuss areas that will be important for the hiring manager to hear. Second, it gives you a sense of whether the reference is a persuasive advocate on your behalf. Both pieces of information are important to be sure you’re connecting hiring managers with people who will make the case that you’re the right person for the job, she says.

Oliver says it’s a good idea to remind your references of some of your key accomplishments and even suggest some of the areas they might highlight. It may have been a while since you worked for or with your reference, and he or she may appreciate the reminder, which can be as simple as writing an email message with a few bullet points of your accomplishments, she says.

“You want people to say something substantive. You don’t want your references saying, ‘Yeah. She’s a great person,” Oliver says. Vague endorsements do nothing for you.

Beshara once had a client whose references raved about his ability to sell to big customers. Since the job was focused on regional and not national accounts, the reference wasn’t relevant and the client wasn’t hired, he says.

Ask your references to focus on outcomes rather than attributes, Oliver says. You may need to help them remember specifics about what you did, depending on how long it’s been since you worked with them. Discussing the impact you had on the organization will be more impressive than the tasks you performed, she says. It’s more impressive to say that you turned around a crisis situation or met several key performance metrics than it is to say that you’re a dependable team player.

While you’re in touch with the reference, it might be a good idea to ask for a LinkedIn review too, Jacinto says. Tread carefully to be sure you’re not asking for too much. However, if the reference is happy to hear from you and enthusiastic about your success, scoring a LinkedIn reference captures his or her feedback for you to use as long as you wish, she says.

Oliver says it can also be a good idea to follow up with the reference after he or she is contacted and ask how the exchange went. You may get important clues about what the hiring manager is looking for by the questions he or she asks, and follow up accordingly with additional information about yourself.

If you didn’t get the job, it’s common practice to discuss why with the prospective employer. Don’t be afraid to ask questions about how influential your references were. This type of feedback can help you know whether your favored references are helping you, need more coaching, or should be taken out of your reference rotation entirely, Oliver says.

Don’t just contact your references when you need them to vouch for you for your next job or gig, Beshara says. Like all good relationships, you need to show them that you appreciate what they’ve done for you, and try to help them, too. If you’re only in touch when you need something, your references might not be so eager to vouch for you in the future. Plus, keeping in touch with them might lead to being considered for openings at their companies, too.