• Ensure that you’re only sending mail to users who specifically requested it. It’s not advisable to purchase mailing lists or subscribe users by having an opt-in checkbox automatically checked on your website.

• It’s preferable to have a double/confirmed opt-in process. When users subscribe to your mailing list, send them an email asking them to click to confirm their opt-in. This will reduce the number of people who sign up from fake email addresses.

• When users subscribe for your mailing list, tell them what mail to expect, how often to expect it, and what it will look like. Set recipient expectations clearly.

Authenticate with Domain Keys Identified Mail (DKIM). This will provide you with a consistent reputation across your domain, regardless of what IPs you send mail from.

Send your email from a consistent email address and advise your users to add that address to their address books or Contacts list. Mail sent to users with your address in their address book or Contacts will be delivered to their inbox with images and links enabled.

Don't send bulk/marketing email from the same IPs you use to send user mail, transactional mail, alerts, etc. Each IP you send from has a reputation. By segregating your IPs according to function, you help ensure that your mail receives the best delivery possible.

• Provide an obvious and visible unsubscribe process in your mail.
• Make it easy for users to unsubscribe from your mailing list.
• Ensure the unsubscribe process is easy to use, such as a one-click unsubscribe web page.
• Users should not have to log into a website in order to unsubscribe.
• Process unsubscribes immediately

A high number of invalid recipients will harm your reputation. You can reduce the number of invalid recipients on your list by using double/confirmed opt-in. You will always have some invalids due to people changing email addresses, but the lower the number, the better your reputation. Be sure to remove invalid recipients from your list immediately.

When users click "report spam", you can get a copy of the spam complaint through our Feedback Loop (FBL) system. Ensure that you have an active FBL on each of your IPs and that you’re processing the complaints quickly. Many senders will treat a spam complaint as an unsubscribe and remove a name from their mailing list if the user clicks "report spam." There are a number of third party tools available to help you manage your FBL.

Brand your mail so that recipients can quickly identify it and won't mistake it as spam. Make sure the From address of your mail clearly identifies who it is from. Also, include your brand in the subject line. Even if users want your mail, they may not recognize it right away.

For more sender best practices, read the Messaging Anti-Abuse Working Group's Senders Best Communications Practices Version 2.0.