No shopper likes that sinking feeling you get in the pit of your stomach as you walk out of a store knowing you just paid too much. But not everyone experiences that feeling–especially those who know how to haggle.

“Surveys have reported that of those who do try to haggle, there is a success rate of 80 to 98 percent,” according to Cindi Fukami Associate Chair and Management Professor in the Daniels College of Business at the University of Denver.

With such a high success rate, it’s surprising more people don’t haggle sellers for a better deal.

“Some folks are concerned about being rejected so they are embarrassed to be looking for a bargain, as if they can’t afford to pay full price,” Fukami says, noting that others are reluctant to haggle simply because they don’t realize they can do so.

It never hurts to ask for a better deal, and Fukami believes confidence is one of the centerpieces of being a good bargainer.

According to Fukami, “The best way to build confidence is to do your homework, both on yourself and on interests of the retailer/provider.” What is the price you are willing or able to pay? At what point will you walk away from the deal? Also, what is the best price on this product/service in your community?”

Shoppers can simply use their smartphones to get information on prices and sales before approaching the retailer to ask for a discount. And when you do ask, do it in a nice way.

Fukami says, “Be likable, for example, be respectful and polite. Try to build rapport by finding commonalities [for example, saying] ‘my cousin lived in that neighborhood,’ and by smiling.”

But don’t give away too much in your facial expressions. “[Keep] a poker face. Don’t look too enthusiastic or too sad [when a retailer responds to your request.] And use silence, which is uncomfortable.”

Fukami, who recommends the book Getting to Yes for any would-be hagglers, says many people are more willing to negotiate when they’re doing it on behalf of a family member.

“There is also support for this idea in the sense that negotiating on behalf of others may induce empathy in the provider,” Fukami notes, with examples such as, “I have to watch my budget carefully. I have three kids that I have to put through college, or I’m a poor student.”

Fukami says you can also use strategies to try to get sellers to throw something in.

“If you can’t get anywhere with the price, seek to add value,” she says. “For example, [asking for free] floor mats to the car, better tires, or tailoring for a suit, a matching tie or belt, or perhaps a volume deal, an existing coupon or buying food at closing time.”

Above all, Fukami says, every good haggler has one common trait–the ability to walk away from a bad deal.

“This is your main source of power,” she says. “If you ask for a discount on a suit and are refused, you have to be willing to pay the higher price or to go buy your suit somewhere else.”