One product, one long web page: this kind of web site is sometimes called a sales letter site or mini-site, and it focuses on one and only one goal, as many sales of that one product as possible. With a one-product sales site, no distractions, no subsidiary goals, such as newsletter signups, are allowed to interfere with that goal. So let's look at some common mistakes and omissions for a sales letter site.

Your headline serves as the key point of orientation for the reader and should be as strongly worded and pointedly targeted as you can manage. Do not use the name of your product as the headline - that's a weak marketing message.

Instead, dramatize either the problem solved by your product or the solution offered, or both. For instance:

Discover Your Family's Roots Through Easy, Fun Internet Research

You can often add a subhead after the headline for even greater punch:

Turn Words into Money with Copy That Even a Skinflint Can't Resist!

Get a Juicier Return on Investment from Your Marketing With the Easy-to-Apply Secrets in This New Manual

Normally you want to start your sales page by building rapport with the reader with respect to the problem or goal at hand. Make sure, however, that you not only make your case in a positive way for your product but also address and head off each and every worry, objection or doubt the reader might have about buying your product. For instance, how can you know so much about knee injuries if you're not a doctor? Or, do these money-saving strategies apply if I live in Canada or Bermuda?

The biggest worry people have buying online from companies or individuals they've never heard of is, are you trustworthy? Am I going to get what I order and have some recourse if it's a pile of crap? A money-back guarantee goes part of the way toward assuaging this, as do testimonials, but just as important, and much more often neglected, is posting a mailing address and telephone number for the vendor.

If it's a physical product that will be shipped, make sure you explicitly say how and when it will be shipped and whether you can ship it anywhere in the world for that price. Don't make the reader click through to the order form to learn how much your product costs, or how much it costs with shipping.

As your copy builds toward its conclusion, remember to include what marketers term the "call to action": explicitly ask for the order. Do so prominently, so that someone skipping down the page can quickly find the "order now" button. Even better, insert an order button or link near the top of the page so that someone who arrives already wanting to buy can do so immediately.

When you've built the strongest possible case for your product and orchestrated your pitch properly, consider the formatting of your sales page. Since this sort of site doesn't have a left navigation bar, the column of text often ends up much too wide for comfortable reading. Studies have shown that paragraphs wider than six or seven inches are difficult to read on a computer screen. Add blank columns to the left and right of your sales copy to narrow it to that width.

Make sure too that paragraphs go on no more than seven lines, and a long run of paragraphs is broken up by subheads. And make those subheads interesting and meaty. Someone who skims down the page should be able to get the gist of your marketing message just from reading the subheads.

Marcia Yudkin is the author of Web Site Marketing Makeover and 10 other books. A four-time Webby Awards judge and internationally famous marketing consultant, she critiques web sites and performs web site makeovers for clients. Learn more about her detailed critique sessions on five different kinds of web sites (including one-product sites) at http://www.yudkin.com/websitequiz.htm .