How many times have you walked into a store, ready to buy -- only to find no one there to help, or even take your money? Or could you see the sales associates but they couldn't seem to see you? Maybe they sized you up as a browser, not a buyer. Or did you find yourself working with a clueless associate, who wanted to be helpful but wasn't, or worse, a pushy associate who would have sold you everything in the store.

No wonder many shoppers actually try to avoid salespeople. A majority of shoppers in a small 2009 study said they won't go to stores to avoid bad customer service, according to researcher Sherry Lotz, associate professor of retailing and consumer sciences at the University of Arizona's John & Doris Norton School. A common concern was that salespeople 'push' merchandise to earn commissions or achieve sales targets. The customers in the study 'did not trust that the store personnel were acting in their best interest,' Dr. Lotz says.

When it's good, though, customer service is a magical elixir that makes customers feel good about making a purchase long after they leave the store. To create this positive feeling, a sales associate must have limitless stores of positive reinforcement, creativesuggestion and empathy.

Sharp salesmen used to pride themselves on their ability to 'read' a customer. Modern sales techniques stress it's best to ask questions, rather than make assumptions. That guy in sweats and a baseball cap is likely to be shopping for designer shoes. 'You have to listen to the customer,' says Claudia Coleman, 56 years old and a top-ranked personal shopper and sales associate at Neiman Marcus's San Antonio store. 'Ask them their favorite color, what they like, what they do -- all these questions to be able to understand their needs.'

There are things customers can bring to get the most out of sales help in stores -- not least of which is an open mind. Once they have worked with an effective sales associate, many shoppers latch on and refuse to deal with others, often making appointments in advance.

Jay Jackson, who works in talentmanagement in Arlington, Va., relies on Chris Sharma, an associate in the men's department at Nordstrom in Tysons Corner, Va. 'I don't buy anything without him,' says Mr. Jackson, who recently came in so Mr. Sharma could select shirts and ties to go with a new blue suit.

Mr. Sharma, 48, has ranked as Nordstrom's No.1 sales associate for the past 10 years, ringing up more than $1 million in annual sales at the Washington D.C.-area store, where politicians and lobbyists are regulars.

He also still works the sales floor between appointments. Recently, he helped a walk-in customer return merchandise. 'I help customers who come in wanting $10 socks,' he says. 'Maybe one day they'll want a suit and remember me.' Mr. Sharma's compensation is based on commission from net sales. Nordstrom says salespeople earn either an hourly rate or commission, whichever is greater. On average, salespeople earn around $40,000 a year, although the retailer says many earn six figures.

It takes a good memory and commitment to tiny details to excel at sales. Mr. Sharma will remember that a customer already has a blue pinstripe shirt in his closet and offer him something else. He isn't afraid to poke a little good-natured fun at some of his customers' fashion cluelessness, but he also plays to their egos. He tells customers if they don't get a compliment on a purchase that he has picked, they can return it. It's a bet he has rarely lost.

On Mr. Jackson's recent store visit, Mr. Sharma considered the blue suit for a minute, then went off to hunt on the sales floor. Mr. Jackson waited by the register. In a few minutes, Mr. Sharma was back with an armful of items. He laid out each one, saying a few words about what he liked about each option. Mr. Jackson bought most of Mr. Sharma's picks, leaving behind just a red tie that he found too loud.

Ms. Coleman, who sells women's apparel at Neiman Marcus, strives to build long-term relationships. The way a garment fits is as important as how it looks, she says. 'I have an education in fashion and merchandising, and I also know how to sew,' Ms. Coleman says. 'I'm a stickler. You see it on a hanger, and it's not the same.' Sometimes, she asks a customer to try a garment on while a tailor is there to weigh in.

Many of Ms. Coleman's customers attend the same charity events and galas, and so she has become know for discreetly keeping track of who buys what for which event. When someone wants a dress that Ms. Coleman knows another woman has already bought, she'll say, 'I'm very sorry, that dress has been sold,' and guide them to something else.

Keeping track of all those moving parts is a challenge. She keeps meticulous notes and memorizes dates and purchases. But she never names names. Like other salespeople, Ms. Coleman follows up purchases with a thank-you note, and she often goes a step further, making a phone call or sending a text to ask how the purchase worked out or to call a customer's attention to something new in the store. She asks for permission before sending customers photos of new merchandise: She wants to gauge the customer's interest in advance but doesn't want to clutter up their phones or in-boxes with huge files.

Nordstrom says it has no formal customer-service training. 'We look to hire great sellers -- people who love to sell. We hire friendly, goal-oriented people who love fashion and empower them to take care of the customer,' the retailer says. Neiman Marcus says, 'Each of our associates is trained to engage the customer and ask the right questions and most importantly, be a very good listener.' The retailer offers online training tools, and associates learn about special events and get demonstrations of new merchandise at regular meetings.

Barry Snowbarger, 43, long a sales associate at a Manhattan Design Within Reach furniture store, has often ranked among the chain's top-five sellers. 'Can I help you?' is something he rarely asks. 'The automaticresponse is, 'I'm just looking,'' Mr. Snowbarger says. Instead, he says, 'I read their body language when they come in. If they are making a beeline, you can tell they're looking for something specific so I'll say something like, 'It looks like you're looking for something specific. Can I help you find it?'' Or sometimes he says, 'Hi, how are you? What brings you in today?'

Mr. Snowbarger says he often spends time chatting with customers to get a sense of their lifestyle, interests and needs. He reads up on new products and designer bios so he can converse with authority and get customers' trust. Sometimes, he says, he'll even visit a customer's home to see the space and help them come up with ideas. In January, Mr. Snowbarger was promoted to a manager position.