1.) Tell the reader they are about to be sold something.
Savvy direct mailers know that the Postal Service requires you to put your return address on the mailer somewhere– but that doesn’t mean it has to be on the front. If the envelope states: “Acme Insurance Services,” you are apt to give it to your crayon-wielding 2-year-old to practice staying within the lines. Getting the letter opened is 90 percent of the battle. If they don’t open it, they won’t read it.
2.) Tell the reader what he will be seeing inside. If you tell the prospect on the outside that they are about to win a million dollars by opening the envelope, many will toss the letter, jaded by past unkept promises. But if you don’t advertise on the outside and instead put your best material on the inside, they will at least read the first paragraph.