A few years ago, I had a call with a potential client--the president of a digital marketing agency. Within minutes he began sharing his (strong) distrust of PR people. He had hired several agencies in the past, he said, all of which had lavished him with praise and promised big things—but none of which had delivered.

I've heard the same story over and over: Client meets PR agency. PR agency makes big promises. Client hires PR agency—and quickly becomes unhappy with lackluster performance. Client fires agency, goes looking for a new agency ... and so the cycle repeats.

So when looking for your next PR agency, listen for the following lines—any of which should serve as a warning.

1. 'You're a Star, Kiddo'

Don’t mistake a publicist’s delusions of grandeur for passion. Hearing compliments feels good, but results are more impressive. "I can see your name in lights" may sound exciting, but the more sincere, realistic—and valuable—promise is: "Your company has the potential to be featured in some cool media outlets for your innovative strategy." If grandiose praise sounds too good to be true, chance are it probably is. Check your ego at the agency door and listen for more concrete plans. If they sound good, you’re probably working with a sound professional.

2. 'I Know Oprah'

There is a big difference between having access to Oprah’s email and having a relationship with the OWN network. Same goes for any big media organization.

Contact lists are always a popular topic with clients: “The last agency we spoke with has relationships with [insert ideal media outlet here]. Who do you know?” There are several tools that can help publicists with their role, including databases of contact details for media outlets, reporters, editors, producers, bloggers, etc. Be sure to clarify whether your would-be agency has a personal relationship—and, even better, prior placements for other clients—or just an email address.

3. 'Yes, Yes, Yes'

I’m all about saying "yes." In fact, I once dedicated an entire month to saying yes to all requests made of me that were not illegal or unethical. (Long story, but I blame Jim Carrey.)

But if you're throwing potential stories out to a publicist, be wary of those who say "yes" to everything. A good publicist will tell you "no" even when it's not what you want to hear. Sometimes that "no" will save you from an unflattering story—or wasted retainer hours.

It’s not unusual for prospects to tell me what some agencies have guaranteed, such as specific story placements. They look to my agency to do the same; when we refuse, they are sometimes disappointed. But our guarantee is always the same: We work diligently to meet the clients’ goals. It may not be sexy, but it’s true—and it does get results for our clients.

As you look for your next agency, find one who is passionate about your brand, sincere in the agency’s abilities—and committed to your company and its vision.

Oh, and by the way: That potential client who despised PR people? He became a client—and is now a big fan.