1. Good Housekeeping
Ensure that your data is clean and that you're not sending the same information to them more than once accidentally. A good marketer stays on top of how often they engage a customer, and you want to be able to track this with certainty.
In addition, people change jobs, residences, phone numbers, and email addresses.
Why is this so important? If you're not getting the information to them, they will forget who you are, and worse, won't contact you when they need something you have. I'm fond of emails. If your list is cluttered with a lot of bad addresses that bounce, it will hinder your ability to deliver to the good ones. The mail service providers will flag you as spam, and you'll end up in bulk folders. How many people check to see if they have anything useful there? Not many.
So keep your data clean, don't waste money sending to people who have changed their data, and consider using multiple methods to track down your client. One tactic is to combine an email with a postcard to obtain a response to ensure that you have their correct information, and follow up with a phone call.

2. Surveys
Everyone loves to give their opinions. Perhaps your clients want something different in their newsletters, or they're looking to expand into an area, and they don't know that you can provide it for them. Perhaps you're thinking of growing your business, and why not survey those with whom you have a positive relationship.

In addition, do a survey on customer satisfaction. How positively do they think of you? Are there areas where you could improve? Then find a way to positively spin and communicate that outward, and people will give you a second chance to impress them.

Should you reward people for taking the survey? You could. In a business case that I recently consulted on, the client sent out email invitations for an online survey, 50% opened, 12.5% completed the survey to receive a 10% off coupon for the online store. Only 1 person in 2 months has used the coupon. Perhaps a greater percentage would have completed the survey for a larger coupon. This can only be determined through testing. The key is to identify what information you're looking for, create a simple survey, and then entice people to fill it out.

Inexpensive online surveys can be found at SurveyMonkey and Zoomerang. If you send a survey via postcard or direct mailing, please make sure you have the return mailing be stamped and self-addressed. This will increase the response rate.

3. Re-activate your account
If your customer signed up at your site to receive a premium newsletter or something else of value, and they haven't been responding, you can pull them back in by asking them to re-activate their account. This can be done with an email or a postcard. It allows you also to clean up your information (as in point #1).

Sometimes people get lazy. Your goal is to remind them that they should look at your mailing. If they're used to getting an email, send a postcard. Remind the customer that they're important to you, and you want to keep them in the loop with your information.

In addition, contacting people 60 days, and then 30 days, and finally 1 week before their paid subscription ends tends to increase the renewal rates.

4. Reminder Services
If you have a good customer management program, you can track the last time someone bought your product or service. A coupon either through direct mail, email, or a phone call at the appropriate time may spur them to sign on. People love having things made easy for them.

5. Rewards programs
Some think that this is a poor way of retaining customers. According to Marty Neumeier's book Zag, loyalty programs fail because they train the customer to expect low prices and wait out normal prices. In addition, they discourage new customers who feel punished or excluded. Once you start down that road, it's hard to go back.

And yet, loyalty rewards programs work like gangbusters for credit card companies and airlines.

So should you or shouldn't you? The answer is evaluate your business model, your competition, and your customer. Don't give away your profit margin if you don't have to. And customers will come back to a place where they feel they are appreciated, and are getting something for nothing. A good way to use rewards and obtain new customers is by offering points for signing up. And refer a friend. If I get points for referring a friend who signs up (and they get points), everyone wins.

The bottom line is to maintain a positive relationship with your clients. Let them know that they are important, and you want to nurture that relationship by providing them with what they need most.