The following excerpt is from Craig Simpson's The Advertising Solution. Buy it now from Amazon | Barnes & Noble | iTunes

Ad legend Robert Collier’s phenomenal success as a copywriter made him a figure that many ad writers and promoters still turn to for advice and inspiration. In The Robert Collier Letter Book, he dissected a series of ads to show what made them succeed or fail. It’s like a graduate course in how to use psychology to prepare effective promotions.

One of the chapters in his book, “How to Arouse That Acquisitive Feeling,” analyzed ads for the degree of emotion they were able to provoke in people. Collier believed (and proved again and again in his own work) that ads that touched readers’ emotions were more successful than ads that only touched the intellect.

Related: 4 Tips for Crafting the Ideal Sales Letter

You can provide a ton of arguments to convince the intellect of the advantage of making a certain choice, but unless you make readers feel that they have to have what you offer and that it will be worth any effort to get it, your sales letter will be worthless.

Collier advised that before writers put even one word down on paper, they need to decide what effect they want to have on the reader. They have to know the feeling they need to arouse so the prospect will be moved to take action. The point of the ad isn’t to make the reader think, “What a clever ad.” Rather, it’s to arouse in readers the feeling of “Let’s go!”

Marketers must determine what feeling has to be aroused to lead prospects to take action. From there, they must consider what kind of argument should be presented to inspire that feeling in readers so that taking action will become irresistible. As Collier put it:

Isn’t the prime requisite arousing in your reader the feeling that he must have the thing you are offering, or that he cannot rest until he has done the thing you are urging him to do?

Of course, people don’t want to feel as though their emotions are being manipulated. They want to believe they’re making decisions based on logic (i.e., you have to placate that good old cerebrum). The challenge of the writer is to present arguments that seem to convince the intellect, while in fact aiming at their emotions.

Collier gives two examples. The first letter had only moderate success, while the second letter pulled more than twice as many responses. Both letters sold boxes of greeting cards, and while the first presented some sound intellectual arguments, the second went straight for the emotions. You can see the difference right in their opening paragraphs:

Letter One -- Intellectual Appeal:

Some people have a sort of sixth sense that enables them to send greetings and the like to all the proper relatives and friends on every appropriate occasion. But most of us are likely to overlook such things.

Compare that to the opening paragraph of the second letter:

Letter Two -- Emotional Appeal:

How often have you promised yourself to keep in touch with some old friend, to cultivate some new one -- and then gone your way forgetting them, and letting them forget you?

The second letter immediately brings up the image of a potential loss readers could experience if they don’t follow up on the offer. It’s that twinge of guilt and loss that keeps the reader going to the next paragraph and the next to learn how to resolve those unpleasant feelings. It primes them to take the easy solution the letter is about to offer.

Related: 4 Advertising Principles from Ad Legend David Ogilvy

The goal of either of these letters is to get readers to place orders for personally inscribed cards so they can get them back in time for Christmas. Let’s look at the final two paragraphs of each letter.

Letter One -- Intellectual Appeal:

The time is getting close now. It won’t be long before you will be wanting to mail these cards. Better fill in your name now on the payment blank -- tell us how many more cards to send you, and drop it in the mail.

Then the days may come and days may go, but you’ll be sure of having attractive greetings with which to keep green all your friendships.

Letter Two -- Emotional Appeal:

And of all ways to recall yourself to your absent friends, none is more pleasant or easier than sending them a lovely Christmas greeting, like the box of fifteen that we mailed to you a short time ago, for they are not only good to look at, but they carry with them a warm-hearted greeting that every friend will welcome.

Remember, it is not the intrinsic value of what you send that counts. It is the spirit that goes with it. As Oliver Wendell Holmes put it, “If uncounted wealth were thine, thou couldn’t not to thy cherished friends a gift so dear impart, as the earnest benediction of a deeply loving heart.

Granted, quoting Oliver Wendell Holmes wouldn’t get you very far today, but it worked well in Collier’s time. The specific words aside, this letter worked because it touched on people’s emotions.

It takes a lot to get people over their inertia, and it takes a lot to get them to consider spending money on anything. Even motivating people to click through to your website takes effort. You have to convince prospects that they’ll feel so much better as a result of buying your product -- that they’ll feel so much better about themselves.

For example, most people know that eating healthy food is good for them, but if you want them to come to your store and stock up on beet juice, you have to play upon their guilt, fear and vanity. So when they come into your store to look through your line of supplements, don’t just talk about the pristine way a certain brand of vitamins is processed. Talk about how much better they’ll feel, how their doctors will be impressed by their healthier numbers and how great they’ll look.

People may also know it’s a good idea to cook balanced meals for their families, but if you want them to keep visiting your healthy-eating blog, add stories about family meals in your own home, the joy of cooking together and funny or heartwarming experiences sent in by other readers. Make reading your blog an emotional experience, not just a list of ingredients and directions.

Whatever you’re selling, try to determine the main factors that impel people to take the action you want them to take, and then appeal to those factors while keeping the intellect happy with arguments that satisfy it. To repeat Collier’s classic quote:

Appeal to the reason, by all means. Give people a logical excuse for buying that they can tell to their friends and use to salve their own consciences. But if you want to sell goods, if you want action of any kind, base your real urge upon some primary emotion!

Related: 6 Steps for Continuous Brand Improvement

People haven’t changed since Collier wrote those words. We’re just as emotional as ever, and that’s still the best way to reach your reader. As a marketer, a good place to start is with yourself. Ask yourself, “What would get me over my inertia so I would take action?”