Check Different ISPs, too

If possible, check your emails when they’re sent through different ISPs. Different email
servers will alter your messages before they even get to the recipient’s email application.
For instance, some ISPs use email servers that will strip any content below a line in your
email that starts with a period (I know, weird, huh?). We’ve been surprised at how
differently email looks when checked in Outlook 2003, but received through:
o Comcast
o Bellsouth
o Earthlink
Send tests to friends and co-workers
If you can’t setup a few test computers, keep your designs really simple, and send each
campaign to a few friends or office-mates. Just ask them to let you know if anything
looks “off” or broken to them.
Or, just use MailChimp’s Inbox Inspector
If you choose to setup your own test machine, and all those test accounts with the
different ISPs, you could easily spend a couple grand. If you also want to check your
campaigns against the big server firewalls (like IronPort, MessageLabs, and Postini)
those are several thousand dollars just to get setup. If you’ve got the money, go for it.
But who has the time to maintain all that stuff?
You can save yourself a ton of time and money by just using our Inbox Inspector. Here
are some screenshots of what you’ll get (it costs less than what you’d charge for one
hour of your time):