Commercial email beats out the next closest online marketing competitor by 100%. According to a report from the Direct Marketing Association, email boasts a return of $40.65 for every dollar spent, leaving it as the highest ROI form of marketing communication available to business.

In order to reap returns that high, companies need to have a strong and engaged subscriber list, with a proven record of being receptive to your message. After over a decade in email marketing, Endai has narrowed down the secrets of list-building to 10 points.

1. Always Opt-In: Never subscribe people without prior permission. Even giving a clear opt-out mechanism will not save you from spam reports, unsubscribes.

2. Allow Customers to Connect: Tie email subscriptions in with other conversion points to allow customers who already like your products to connect via email. For example, offer email subscription as part of the checkout process.

3. Don’t Make Subscribing an Afterthought on Your Website: We notice a lot of companies ignoring their mailing list sign-up on their websites. Don’t throw it in as an afterthought. Plan your subscription funnel with the same rigor that you plan your sales funnel.

4. Cross-reference Email Content with Other Channels: If you have a popular blog, Facebook page, or Twitter stream, mention content found in your newsletter and link to it with an invitation to subscribe. A simple link and invitation can introduce a large and untapped audience to your mailing list.

5. Give Something to Get Something: An email address is inherently valuable, and your customers recognize this fact. Bartering something of value to your customers is a great incentive for them to volunteer their contact information.

6. Don’t Give Too Much: You want every person signed up to your list to be engaged with your company, not simply with a promotion you’re running. If the only reason they signed up was to receive a gift, they probably won’t stick around. Your gift should be just valuable enough to counteract the cost of subscription; not act as a primary motive.

7. Actively Monitor Your Mailing List: A subscription should not be the last step in your email marketing plan. Monitor the way your list behaves, and use that data to modify your content strategy.

8. Analyze, Test, Modify: Your email strategy should be a constant cycle of analysis based on past behaviors, testing multiple options, and modifying future emails based on results.

9. Segment on Behavior, not Self-Reported Demographics:Segmenting your list is critical. Make sure that you are segmenting customers based on their interaction with your content, not on preconceived notions of how demographics should behave.

10. Be Clear and Consistent: Make sure that every single subscriber on your list is aware of when and how often you send emails, and make the purpose of each email clear. A lack of consistency in timing or messaging can serve to scare away subscribers and drastically increase your spam report rate.

A good email list can be an incredible asset to a company, while a poor one can be useless at best and a liability at worst. By following our ten simple points, you can watch the effectiveness and ROI of your email list grow dramatically, along with your bottom line.