Offer freebies to your subscribers. However, don't overdo it. When people get used to receiving freebies too often, it would become difficult to get mailing list them to fork out money for your products or services. Many email marketers make the fatal mistake of flooding their mailing list with nothing of value but thinly disguised sales pitch. If your subscribers can get benefits from your newsletters, they will look forward to your mailings.
You got to feed the goose that lays the golden eggs. Maintain your opt-in list, and you'll have a list of happy and eager subscribers. This mailing list translates to potential sales. List building, is something that any online marketer must know and learn about. List building, is essential because your mailing lists determine the amount of people who receive your newsletters.
The "list, is a list of your prospects and customers, if your list starts increasing and then plateaus (does not increase after a period of time) you might be doing something wrong with the newsletters or whatever it is that you're doing. Here mailing list are good tips on building your lists, and probably improving on your sales too. See the Value of Every Email Address Not every e-mail address is important.