1) Test your e-mails against anti-spam technologies. Make sure you are testing your messages against the most popular corporate anti-spam technologies, such as Brightmail, Postini and MessageLabs.
2) Make sure your e-mails render correctly. Test your e-mails to make sure they look the way you intended in the most common e-mail clients, such as Outlook.
3) Understand the domains on your list. If there are certain corporations that dominate your customer list, try reaching out to those system administrators to help improve your delivery rates.
4) Include an "add to address book" call to action. If customers add your sending address to their address book, it will increase the likelihood of reaching their in-boxes.
5) Ensure your system is set up correctly. Having an inappropriately configured e-mail delivery system can affect your delivery rates. If you have an open relay or your DNS is not configured correctly, this will affect your overall delivery rates.
Spencer Kollas is director of delivery services at StrongMail Systems (www.strongmail.com), a provider of e-mail delivery software and appliances.