Spot check your HTML
Make sure your email looks good in a few different browsers. Some browsers and email clients may handle HTML differently, and the best way to spot check for any errors or typos will be to try sending to a few different addresses. It will be worth the few minutes to make sure everything looks exactly how you expect, and that links point to the right place. Don't be caught by any surprises when your email send goes out.
Send a preview to a yourself and a friend
Click the Send Preview link to enter a few test email addresses. Your preview will be sent as a live email, and will be delivered to the recipient's inbox. This will allow you to check what a fan would see upon receipt of your email blast. When you've confirmed that your send is ready to go, check to box to confirm recipients and your email will begin processing for sending. Also see: setting up a scheduled send.
Note: Emails sent as previews will not be tracked and metrics will not be counted. Test as many times as you need to make sure everything is just right.