Sales letters are powerful selling tools. They give you a simple, direct way to generate sales leads and orders. But for many businesspeople, they present a daunting writing challenge and a host of questions to consider. How do you start a letter? When should you present your offer? How long should the letter be?

I've been writing successful direct mail, including sales letters, for many years. And I've learned that writing a letter is like building a house. You must go step by step and put every element in the right place.

Here are 10 tips for building your own successful sales letter.

1. Consider headlines and photos

If you want your letter to appear businesslike or highly personal, I suggest that you not use a headline or graphics. However, many types of sales letters can benefit from either or both.

I often use those items for straightforward consumer mail. In a newsletter subscription offer, for example, I showed a large photo of the newsletter at the top left of page one, with a bold benefit headline on the right side. I also included a reference to the offer and a call to action.

These techniques liven up the letter, draw the eye, telegraph the offer and the main benefit, and push the letter text to the lower half of the page, making it shorter and easier to read. If you can get someone to start reading a letter, you've won half the battle.

2. Use a fitting salutation

If your budget allows, go for personalization. Any letter I receive that starts with "Dear Dean Rieck" is far more likely to get read than one with a generic salutation.

But if you can't personalize, use a salutation that connects with the reader as closely as possible in the context of your list, offer, and product. "Dear Cat Lover" for cat owners, for example.

If you're mailing to a business audience, you can use the recipient's occupational or professional title, such as "Dear Family Doctor" or "Dear Marketing Manager." If nothing else, "Dear Friend" is usually a safe bet.

3. Start your letter strong

There are infinite ways to begin. However, I generally try to create something that's short, attention-grabbing, and maybe even a little startling. Here's an example from a letter I wrote to sell a home-buying book:

Dear Friend, 
      I could just kick myself! 
      A couple years ago, my wife and I bought a new home. After we moved in, our neighbor asked us over for coffee. 
      What a shock! He had the same house design, but it was full of all the extras we couldn't afford—like a fireplace, panel doors, tile, oak cabinets. It was stunning.
      When I asked how much it cost, he smiled. "Nothing. I knew how to get the extras added on free." And it was so simple, I could have done it, too. If I had only known the secret!

Notice how punchy and intriguing the first line is, and how the copy plunges right into the meat of the sales pitch with a story chockfull of specifics.

Of course, a letter opening doesn't have to be this involved. Sometimes it's best to get right to the point, as I did in a business-to-business lead generation letter:

Dear John Doe,
      I have a FREE Demo CD you should see. May I send it to you? 
      It demonstrates (the product) and how dozens of leading companies are using it to revolutionize the way they work.

4. Introduce your offer on page one

I've seen wonderfully persuasive letters in which the offer appears at the end of the letter. But my rule is to present the offer, in some form, on the first page.

When I use the headline approach I mentioned earlier, I usually present the offer after the header material and before the salutation. Then I try to include a reference to the offer again in the letter text on page one.

5. Break your first page mid-sentence

Whether because of curiosity or an urge for closure, readers are encouraged to flip the page and continue reading when a sentence doesn't end at the bottom of the page and continues on the next page.

I always use this technique on page one—and, whenever possible, on odd-numbered pages that follow.

For multipage letters printed on one side only, you might consider doing this on every page, though doing so could become annoying in letters longer than four pages.

Anywhere the reader must physically turn a page, consider adding typed or handwritten kickers (lower-right of the page), such as, "More" or "Over, please."

6. Fill the letter with specific details

The body of a sales letter should include benefits, facts, testimonials, and specifics of whatever kind required. However, the letter is not the place to dump every detail of your product or service. Its job is to make a personal connection with the reader and present a sales pitch.

If you have an enormous amount of supporting information, put it in a brochure. Letters and brochures should not duplicate one another. As they say, "Letters sell; brochures tell."

7. Make your letter as long as it needs to be

When asked how long a man's legs should be, President Abraham Lincoln replied, "Long enough to reach the ground." He was joking... but also making a point.

A letter should be just as long as it needs to be. No more. No less.

Most true sales letters (where you're asking for an order) run 4-8 pages. Longer letters can work for information-intensive products. Shorter letters can work for lead generation and very simple offers. An experienced writer should have a sense for what is needed to do the job.

Don't decide on the length based on mailing cost alone. If you want to cut costs by trimming your letter, I suggest writing a longer letter first and testing it against a shorter version of the same letter. A fundraising letter I once wrote, for example, tested equally well at eight and six pages, so we knew that the cut would save money without hurting response.

8. End your letter when you're finished selling

Many sales letters don't know when to quit. You should state your full offer, guarantee, and a clear call to action. Then stop writing. Here's how I ended that business-to-business letter I mentioned earlier:

      Ask for your FREE Demo CD today! It's ready and waiting. I just need your OK to send it to you. There's no cost. No obligation. 
      Just go to (company website) and ask for it. I'll send your FREE Demo CD as soon as I hear from you.

9. Have the right person sign the letter

Often, the signature is that of a person of high authority, such as the president of the company. But it could also be a vice-president, editor, publisher, inventor, marketing director, or spokesperson.

This decision shouldn't be "political." Ask yourself, "Who would make this offer? Who would people expect to make this offer? Who would people be most inclined to listen to and believe?"

When possible, print the signature in blue to make it appear more personal. Also, pay attention to how the signature looks. If it's shaky and ragged, like the signature of a mass murderer, have someone else sign the name.

I often have my designer forge signatures to create a more confident look. And it has the side benefit of added security: You won't be revealing your actual signature to anyone.

10. Don't forget the postscript

People like to know who a letter is from, so they'll often glance at the signature at the end of the letter before they read anything. Therefore, because of its proximity, the postscript is in a visual hot spot.

A postscript should be relatively short—ideally three-to-five lines—and should present an important message, a prime benefit, a restatement of the offer, a reminder of the deadline, or whatever you feel is most effective.

* * *

Let's face it. It takes a great writer to write a great letter. So it's often best to call in a pro.

But if you face a letter-writing situation yourself, follow these 10 tips. You'll end up with a better, stronger sales letter.