1. You can use the following services to test the spammyness of your campaigns
  2. Check for blacklist and domain reputation at the following sites
  3. If you are a google apps user, make sure you check the MX addresses by the following tool
  4. It is important to follow the guidelines of Google on bulk emails and follow the same
  5. If you see Gmail flagging your email as spam, you can contact their email delivery team to rectify any issues.
  6. READ these articles to learn more about Email Deliverability and the Best Practices 
  7. Try to avoid the Spammy words listed in this article
  8. If you are blacklisted, below are links to the Delisting forms used by the more popular external blacklisting services:

  9. Some more useful links