Headlines are the most important part of a print ad.

In fact, David Ogilvy, famous ad man and author of Confessions of an Advertising Man, has said that four out of five people only read headlines. Nothing more.

And if people DO choose to read the rest of the ad, they make that decision based on the headline.

That's a big job to put on the shoulders for what amounts to a few words.

But before you start despairing over your headline-writing skills, take heart. There are several "headline types" that have proven to sell products and services over and over again. Below are four of the most powerful and the easiest to implement.

1. How to. Everyone loves a how to headline. How To Quit Smoking in 30 Days Or Your Money Back. How to Write a Novel in 30 Days. How to Lose Weight Fast.

Why do these headlines work so well? Because they promise a solution to your customers' problems. Why else do so many nonfiction books have how to in the title? If the how to is addressing a need, you feel almost compelled to pick the book up and look at it. Or, in the case of marketing materials or articles, this same natural curiosity can entice you to keep reading to discover the answer.

Keep in mind the better the benefit, the more likely you'll catch your customers' attention. (The benefits in the above headlines are quitting smoking, writing a novel in a month and losing weight. All of these can be powerful benefits.)

2. Question. These headlines ask a question (obviously). If you want this headline type to work, it better ask a question that your customers want an answer to. Are you spending too much on your car insurance? Will your marriage fail? Will you know what to do if you're in an accident?

Whatever you do, don't ask a question that only your business cares about. Something like: Do you know what our company has been up to lately? Again, focus on the benefit for the customer.

3. Top ten reasons. Okay, it doesn't have to be ten reasons or even the top reasons. But just as everyone loves how to headlines, they also love top ten reasons.

Four headlines that work. Five ways to fix a broken toilet. Seven warning signs that your house may be making you sick.

Again, the customers see the benefits immediately. Plus, they know exactly what they're getting -- so many reasons for something.

4. Testimonial. This headline uses your customers' words to sell your products or services. This works because people see proof up front that your product or service does what it's supposed to do. If used correctly (meaning people believe it really is a testimonial from a real customer and not something fabricated) then this can be a very effective strategy.

If you choose this headline, put it in quotes so it's obvious it's a testimonial. And use the customers' words as much as you can to make it sound authentic. Whenever possible, get permission from your customer to use his/her name. You may even want to consider adding a photo as well.

(For more headline and copywriting tips, see Robert Bly's book The Copywriter's Handbook.)

Creativity Exercises -- Write those headlines

Get a stack of paper, find a couple of pens (I'm partial to gel colored pens) and let's start brainstorming.

Start by making a list of all the benefits of your product, service or business. (Benefits, not features. Benefits are what your customers will get out of your product.)

Put that sheet of paper aside. Now pick a headline type and write it on top of the paper. For instance, Question headlines. Underneath start writing as many different types of question headlines you can think of. They don't have to be pretty, they just have to be a question.

Come up with at least 50 of them. Don't let your brain or pen stop until you do. No matter how painful. If you get stuck, go back and look at your benefits list and pick a different benefit.

I practically guarantee by the time you reach headline number 50, you'll have written at the very least one pretty darn good headline. You might have even uncovered a brilliant one.

Try this same exercise with all the headline types and see what new ad concepts you uncover.