I frequently speak with many beginner email marketers and am always surprised at how many don’t use a seed list to test their message before and during a mailing.
Ideally you want to have multiple seeds for as many providers as possible. There are also services that you can use that will provide you with seeds and make it easy to check the delivery of them.
At the very least you could set up multiple free accounts with gmail, hotmail, yahoo and aol, as they will most likely make up the bulk of your list anyway, assuming you mailing mixed lists. It also can’t hurt to set up accounts with other popular free providers.
Always send a mailing using you seed list before you do a mailing and check to see how your delivery was. If there was a problem, then you can make changes to try and improve it, assuming it’s not an IP issue. You should also include the same seed list during any mailings, so you have an idea how well it sent.
In addition you should know the percentage makeup of each of the domains in your list. Then if you find that your mail for say hotmail hit the junk folder, you know exactly what percentage of your mail wasn’t delivered. This is especially important if you find a problem with a domain that makes up a large percentage of your list, such as gmail.
If your using an autoresponder service and you have determined that the problem isn’t on your end, then you can contact them to see if they are aware of the problem and are working to fix it.
You can also set up free trial accounts with different autoresponders and send your seed list to see which has the best delivery.
As you can imagine, the bigger your list becomes, the more important this this is to do.