After all is said and done, you’ll be left with a handful of people that have come in and transacted business with you based purely on your piece of mail. You can track this in any number of ways (coupon codes, requiring them to bring the mail in, comparing sales numbers from highlighted items on sale versus when they’re not, etc.), but be sure to track it in an easily manageable fashion. This will allow you to re-engage with those customers with whom your mail marketing was successful.
Once your list is targeted, you need to spend an equally large portion of time coming up with a great deal – even if it means you might lose a bit of money on it. The underlying goal of any marketing campaign is to gain new customers, and it’s worth it to significantly reduce your profit margins to gain said customers. Once you have a surgically-honed list and an amazing offer, then you can spend some time on the design, copy, delivery methods, postage rates, date of delivery, size of the mailer…there are a lot of other options to consider, but following the 40/40/20 rule you can see how important audience and offer truly are.