Published by A.W. Shaw in 1921, 72 Letters and What Made Them Pay is just what it says. It is a collection of 72 letters, chosen from over 5,000 letters that had made big sales. These 72 are analyzed and dissected in such a way that you will be able to create letters of your own that get the kind of returns you want.

For instance, one common denominator of these powerful letters is that they begin with an interesting hook. The hook may be in the form of a story, such as, “There is a man in Boston who has a unique way of making a living.” It may be in the form of a request for help, “Will you do me a favor?” It may even offer a gift, right from the get-go: “With your permission, I'd like to send you…”

One master letter writer was Robert Collier. He's the one that conceived the idea of the “Will you do me a favor?” letter. He had heard about a manager who asked a competitor for advice in handling customers who took advantage of their terms. This technique turned a competitor into a friend and helped bring the two companies together.

Collier decided to use this technique in print to sell “Keepdry” raincoats. Collier wrote in the voice of his client, asking the prospect to wear one of his new coats for a week and return a survey that would give an opinion of the coat. If the prospect liked the coat, he could keep it at a “discount” price. If not, he would simply return the coat, along with his honest opinion. This particular letter was responsible for selling 20,000 raincoats.

Today, it's even easier to give people something of value in return for their opinion. If you operate your business offline, you can offer coupons and ask for opinions by direct mail. If you work online, you can offer some online product in exchange for customer opinion, as long as the product you offer is useful. By asking people for their opinion and giving them a gift, you make friends who become interested in what you have to offer.

Referrals from current customers also make use of the personal touch. An example from 72 Letters and What Made Them Sell came from a golfing club that wanted to increase its membership. It was signed by the chairman of the club, a man named Davis, and began:

“The other day I met a friend of yours…He handed me your name and said, ‘There's a fellow, Davis, that I'd like to see join the club.'”

This letter had such personal appeal that many people actually wrote a personal letter in reply! The letter pulled a massive 30% return, and many other organizations have used the same letter, in one form or other, ever since.

No matter what your line of business is, you can apply the same principles to your letters. Ask you customers to do you a favor. That may be in the form of a referral, or it may be feedback your products, services, or even the design of your website. Once they've done you a favor, they feel invested in your success, and you've turned customers into friends who will support your business for years to come.