While most marketers understand that selectivity and person-to-person communication are the primary benefits of direct mail, they often neglect to use the time-tested techniques that have been documented by successful marketers for decades.
What is the most important element in a mail package? The letter hands down. The proof is seen in hundreds of split-run tests between letter-based mailings and other packages. The ones with letters almost always out-pull those without.
Which mail package or format is most successful? The classic direct mail package consisting of outer envelope, a letter, an enclosure, and a reply card or fax form has proven to be very effective. Why? The pros say the letter serves to introduce the subject, cite the key benefits and clearly ask for action. The enclosure supports the letter and expands on the product or service adding the details that drive response and build credibility. The reply card or fax form make it easy to respond.
The second best-pulling package is a letter and response card or form. It's also evidence to support the pros' claim that the most important element in any package is a letter. Why? First, it's a familiar document to all. People feel comfortable reading letters and they know how to read them. Secondly, a letter is the most personal of communications and exploits one of the inherent strengths of the mail medium.
That said, the right answer is the package that's strategically-sound for the task at hand. For the best results, you'll need to test formats: self-mailer versus envelope mailing, postcard versus self-mailer, business letter versus graphically-enhanced pamphlet.
Should my letters always be a single page? No. In fact, a two-page letter will almost always out-perform a single-page letter. Why? Presumably the longer letter has more useful information for the recipient. This presumes you have enough material to require additional pages. The point is, take as long as you need to tell your story fully. Just make sure it's tightly told.
Is teaser copy on envelopes helpful in getting mail opened and read? Absolutely! You only have a few seconds to capture and hold attention. If the outer envelope is blank, there's no compelling reason to open it now. Or maybe ever. An exception here can be mailings to established customers. When you have a relationship, you can assume your mail will be opened without the nudge that envelope copy can provide.
Which drives more response: a window envelope or a plain envelope? In most cases, it doesn't matter. A common misconception is that a window envelope makes the package look like an invoice, a check or something else typically handled with greater urgency than a normal letter. This is not so. And since window envelopes cost more than plain ones, the extra cost isn't always justified.