Several factors can lead to your email program's success or failure. Understanding how an email is delivered and following certain best practices can increase your chances of reaching your customers' inboxes. Even when you have customers' interests in mind, you may still encounter situations that impact your messages. The following sections contain recommendations to ensure your email communications reach your intended audience.

Authentication

1. Authenticate your domain with SPF. Sender Policy Framework (SPF) is an email validation standard that prevents email spoofing. Domain owners use SPF to tell email providers which servers can send emails from their domains.
2. Sign your outbound mail with DKIM. DomainKeys Identified Mail (DKIM) is an email security standard designed to ensure that the domain owner authorized an email that claims to have come from a specific domain. It uses public-key cryptography to sign an email with a private key. Recipient servers can then use a public key published to a domain's DNS to verify that parts of the email have not been modified during the transit.
3. Test your authentication settings for SPF and DKIM by sending an email to an ISP-based email address you own, such as a personal Gmail or Hotmail account, and then view the message's headers. The headers indicate whether your attempts to authenticate and sign the message were successful.

Domain and "From" address considerations

1. Think carefully about the addresses you send emails from. The "From" address is one of the first pieces of information your recipients see and, therefore, can leave a lasting first impression. Additionally, some ISPs associate your reputation with your "From" address.
2. Avoid using a no-reply address, such as no-reply@example.com, as your "From" or "Reply-to" address. Using a no-reply@ email address sends your recipients a clear message: that you aren't offering them a way to contact you and that you're not interested in their feedback.
3. Ensure that the WHOIS information for your domain is accurate. Maintaining an honest and up-to-date WHOIS record demonstrates that you value transparency and allows users to identify whether or not your domain is legitimate quickly.

Maintain a Clean List

1. Implement a double opt-in strategy. When users sign up to receive an email from you, send them a message with a confirmation link, and wait to start sending them emails until they confirm their address by clicking that link. A double opt-in strategy helps reduce the number of hard bounces resulting from typographical errors.
2. Perform minimal validation on addresses collected with a web-based form. For example, ensure that the addresses you collect are well-formed (that is, they are in the format recipient@example.com) and that they refer to domains with valid MX records.
3. Use caution when allowing user-defined input to be passed unchecked. Forums registrations and form submissions present unique risks because the content is entirely user-generated, and spammers can fill out forms with their content. It's your responsibility to ensure that you only send emails with high-quality content.
4. Avoid sending emails to standard alias (such as postmaster@, abuse@, suppor@, or noc@). Ensure that you only send messages to real people who want to receive them. This rule is especially true for standard aliases, which are customarily reserved for email watchdogs. These aliases can be maliciously added to your list as a form of sabotage to damage your reputation.