Poor list selection is the worst mistake you can make in direct mail. When you mail to the wrong list, you get experience - which is what you get when you don't make any money. No one orders at all. Chevy hubcaps to Buick owners. Radios to the deaf.
Bottle caps to a tuna factory.
So here's how to correct it. The more precisely you can define your perfect target audience, the better you'll be able to aim your mailing, the better your response will be. And the name of game in direct mail is to maximize response per thousand - to make that one extra person in 1,000 stop, look, pick up the phone and call. But without knowing who your target market is, you certainly won't score any sales. You know, direct mail really is like shooting fish in a barrel.