Any retail outlet will tell you that the only thing harder than getting a customer through the door the first time is getting them back for a second time. Marketing isn’t just about the one-off purchase—it’s about nurturing your customers over a lifetime of purchases, and relying on their regular business for your sustained success.

Online retailers are even more vulnerable to shifts and changes in customer spending and retention habits. If you’re moving a good product or your service is excellent, you’ll enjoy a great deal of customer retention without even trying. If your product or platform isn’t naturally something that customers will come back to, though, you have to strain extra-hard to keep customers coming back to you instead of going elsewhere.

Here are a few tips for retaining your customers with foolproof marketing strategies that can pay off for your business.

Appreciate Your Customers: This should go without saying, but it’s shocking to see how many businesses hardly care about their customers. Retailers that take the time to compose a genuine “Thank You” message after a transaction—even if it’s just in an automated email response—will win over their customers’ trust and respect.

If your products are more high-price and less high-volume, or you only have a few monthly clients, you should consider writing and signing a note of appreciation and addressing it directly to your customers. Whatever you do, make it clear to your customers that you honestly appreciate their business.

Monitor and Motivate Your Critical Customers: If you deal in regular high-volume purchases, you should be keeping detailed metrics on who your best customers are, and whether or not they’re on-track for their typical spending amounts each month. Monitoring all of your customers and flagging those that have dropped off your radar for regular purchases is ideal.

Finding flagged customers that are lagging behind in their usual purchases and presenting them with a special “welcome back” deal is an excellent way to not only bring them back to you, but keep their loyal business long into the future.

Keep An Ear To Suggestions and Complaints: Complaints and customer input are often seen as an annoyance to many business owners and retailers. Who are your customers to tell you how to do business? In the online world, though, your customers are exactly who you should focus in on when it comes to improving your operations.

Customers are on the end of all of your design, marketing, and selling efforts. They are your eyes and ears into exactly how effective your business is in other customers’ eyes. Customers that are vocal about their experience with your retail site aren’t just complaining—they are passionate about their purchase and are frustrated by problems because they initially wanted to purchase through you.

Selective Customer Retention: Focus On Loyal Buyers
After a customer joins your site, you should see trends within their buying patterns within months that will show you exactly how valuable they will be to your bottom line. Just as you should keep track of customers that are lagging behind on regular purchases, you should also keep track of customers that are high-value assets to your operations.

Customer segmentation is an excellent tool that can help you hone your marketing strategies and perfect your plan of action as you move forward with your business. Forming behavior-based customer segmentation profiles will give you a clearer picture of who your most valuable customer really is, and how you can appeal to their tastes and attract more customers like them.

Encourage Customers To Share The Good Word About Your Products
Customers love engagement with a favorite brand, and reaching out to your current customers and offering incentives for them to bring their friends to your products and services is an excellent way to engage and retain your best performers. With the right deals, you can even make sharing and referrals a fun, entertaining experience.

Referral programs and other share-based incentives are great ways to attract like-minded business directly to your site through your current customer base. There’s no better asset than a valuable customer, and chances are they keep company with others just like them. If you can motivate your core to bring in more potentially successful customers, you should reward them—and consider the additional customer savings an expense of your referral campaign.

Jaime Brugueras is a 10-year marketing analyst veteran and the co-founder of Mineful, a customer segmentation software () for online retailers. Follow me @brugueras on Twitter.