Attracting new customers is an obvious way to grow your business, and often the primary focus of a small business owner. 

But like any important relationship, experts say it's what you do after you win the business that really determines long-term success. 

Here are five cost-effective ways to keep customers coming back without coupons, gimmicks or giveaways.

Don't wait for complaints to step up the charm. Use a personal touch to cement the relationship with your most loyal customers. A simple handwritten card letting them know you appreciate them will stand out far more than a mass e-mail. 

In a high-tech world where few people put pen to paper anymore, receiving a snail-mail note makes customers feel special, said Lauri Flaquer of Saltar Solutions, a small-business consultancy in St. Paul, Minn. 

Making an unexpected phone call to check in with the customers who bring in the greatest revenue,  for example, will also leave a lasting impression. And be consistent, Flaquer recommended. Contact them every 30 to 90 days, but remember that it should always be a sincere gesture of appreciation -- not an attempt to sell them more stuff. "You don't want to just call when you need them."

Start from the inside out. Experts said you also must consider the trickle-down effect your employees have on the customer experience. 

"Look at how you're treating your employees. Are you setting them up to serve customers in a way that makes the experience special, unique and different?" said Lise D'Andrea, president and chief executive of Annapolis, Md.-based Customer Service Experts, Inc. 

She suggests surveying your team regularly, asking about their interactions with customers. You can also create a "service purpose" that underscores your customer-centric focus

"Write down three to four steps that define how [you and your employees] are going to interact with each other and the customers," D'Andrea said. Then, make sure your team knows how they're expected to support those standards, such as being welcoming to everyone, offering support and being respectful."

Personalize the connection. Look for ways to celebrate your customers' successes that have nothing to do with you. For example, if you own a tech company and the law firm you developed software for just won a major award for their pro-bono work -- make a point to acknowledge it. 

Flaquer said it's fairly simple to find out about customer accolades by subscribing to customers' own newsletters or even setting up a Google alert.You can also publicize their successes in your own company newsletter.

"It shows customers that you value them and you're paying attention," said Flaquer. "It's a huge value-add that doesn't cost your company any money." 

Reaching out to customers on a social level can also personalize a connection that might otherwise remain strictly transactional, according to D'Andrea. She recalls a creative services agency that threw a party every year based on jambalaya, a spicy Creole dish -- and invited its customers to join the fun. 

"Each person was also asked to bring a specific ingredient, so everyone contributed to the food being made," D'Andrea said. "It was a fun, different way to bring customers closer; they were all pulling together on something that had nothing to do with business."

Create an inner circle -- and let them in. If you're developing a new product or program, consider bringing in your most loyal customers to serve as a focus group. "This way you're tapping the customer as a resource and developing a different type of relationship, which is actually more of a partner," D'Andrea said. "You're showing you appreciate the feedback and value their input." 

Ask them their opinion on your new offering. What do they love about it? What do they think is wrong? Would they even use it? Asking specific questions and really listening to their answers can not only build customer loyalty--but also help build your brand.

Pay attention. One of the simplest, yet oft-overlooked, ways to keep your customers coming back is to pay attention. Stay alert to potential problems and ask for feedback. Do it early and often -- and be specific. 

If you don't think they'll tell you the truth directly, D'Andrea suggested sending a link to an anonymous survey and posting the link on your Web site so it's always available if they choose to complete it. "[Business owners] focus so much on getting, getting, getting and pulling in the fish, and then they forget to ask all along the way how things are going," D'Andrea warned. "You have to keep a pulse on what's happening with your customers."