Of course my advice to marketing folks who want to write their own ads should be, Don't—use a pro writer like me. (We're really good, and we've got mouths to feed.)

But when you want or need to write ads or promotional text yourself, here are some tips that will help you come up with a message and concept that work.

To keep this simple, we'll use Joe the carpenter as our metaphor. I know carpentry doesn't have a lot in common with major business corporations. But the principles of how to approach promotional writing are identical, whatever the subject matter.

So what have we got (with no frills)?

Joe the carpenter is really good at making things out of wood.

We'll get a lot more done a lot faster if we forget that and instead focus on what we want to achieve.

Joe wants to increase and consolidate his business as a carpenter specializing in woodwork for people's homes in this area.

Now we need to figure out the best way for him to do this. In the advertising world, this would be handled by the planners/account team etc.—not the copywriter.

But we're talking DIY (do-it-yourself) here. So the first step is to take a closer look at Joe's target audience. Who are they, and what do they want from carpentry?

Joe the carpenter's potential customers are well-heeled local homeowners who are prepared to pay well, but only for high quality work and service they can depend on.

What do we deduce from this? Obviously, a low-price story won't impress them. In fact, if anything, it will put them off Joe.

What is likely to work is a quality story. Also, we notice an element of insecurity here, too, which we can use to help establish Joe's reliability. (More about that later.)

The next consideration is how are we going to get our message to the marketplace. This can affect what we write.

Joe the carpenter will use quality leaflets hand-delivered to targeted homes. (If he had an appropriate email list, he could use that instead. The following concepts would work across pretty much all relevant media.)

That means his message should be very personal, from me to you. The leaflet (or email) is great because it's highly targeted and there'll be little or no waste, but we'll have to grab them by the throat from the first line or our message will be in the trash bin.

Now, what have we got to offer that other carpenters haven't? Why should people pick up the phone to call him? Why should they trust him with something as important as the contents of their homes?

Joe the carpenter is highly skilled.

He has 20 years' experience.

He's a local man, born and bred.

He's worked for some of the city's most respected residents—including the Mayor—for many years.

He has glowing testimonials from many of his customers who are prepared to say so if a new customer wants to ask them.

That's all excellent stuff, but there's a problem here. Those are features, not benefits. Features are what something or someone is (so what?) and benefits are what it/he/she does (for me? That's more interesting…). If you want to write good promotional material, remember this cute little phrase: features smell, benefits sell.

It's easy to turn a feature into a benefit. Just add a “so” at the end of the feature and fill in the blank. Like this...

Joe the carpenter is highly skilled—so he knows what he is doing and you can rely on that.

He has 20 years' experience—so he won't waste your time or money because he knows what works and what doesn't.

He's a local man, born and bred—so he's not likely to do a moonlight flit having half-completed your work, because people know where to find him.

He's worked for some of the city's most respected residents, including the Mayor, for many years—so the guy must be doing something right.

He has glowing testimonials from many of his customers who are prepared to say so if a new customer wants to ask them—so we have proof that he's doing something right. These days, testimonials have to be legally true.

Now, we need one key benefit for our message to lead with. This is what ad folks call the USP—the Unique Selling Proposition. You get that by asking what does all this really boil down to?

First the feature...

Joe the carpenter is acknowledged as Ourtown's leading quality carpenter for people's homes.

And then the resulting benefit—what does this do for you?

Joe the carpenter gives you high-quality carpentry you can really rely on.

So how do we get our message to portray that benefit? We portray it by implanting a sentiment in our message—one that instantly captures the benefit.

Sentiments don't have to be touchy-feely. They can be based on anything from sex and rock and roll to hard-nosed financial or management issues. Whatever the choice, the secret of a message that works is to choose the right sentiment and then use it so the audience immediately grasps the benefits of buying your product or service.

In this case, by adding a sentiment into our message, we see a powerful benefit coming through:

Because you really care about the quality of everything in your home, only Joe is good enough to do your carpentry.

That's lumpy. So let's develop a concept that says it in a shorter but sharper way. (Concepts are prettied-up versions of the message, on which you then base your final headlines and copy.)

Only you value the quality of new woodwork in your home as much as Joe the carpenter does.

I like that as a concept, but it might be seen as not hard enough, even for this end of the market. What about a concept that touches on the insecurity issue (mentioned above) as well?

The dependable handcrafted carpentry service your home deserves… now available from Ourtown's leading expert, Joe the carpenter.

Or this, making even more of that insecurity...

Chances are, most carpenters could do a good job on the woodwork in your home. If you don't want to leave it to chance, call Joe the carpenter.

This is the approach I use when writing ad or promotional copy. Other pro writers will use a slightly different approach. But there will be many common denominators, because the basic method works.

If I had to pick a single element from this as the most important of all, I'd say remember my cute little phrase: features smell, benefits sell. If everything you write for this purpose is benefits led, you won't ever go far wrong.