Regardless of what you're trying to sell, you really can't sell it without "talking" with your prospective buyer. And in attempting to sell anything by mail, the sales letter you send out is when and how you talk to your prospect.
All winning sales letters "talk" to the prospect by creating an image in the mind of the reader. They "set the scene" by appealing to a desire or need; and then they flow smoothly into the "visionary" part of the sales pitch by describing in detail how wonderful life will be and, how "good" the prospect is going to feel after he's purchased your product. This is the "body" or "guts" of a sales letter.
Overall, a winning sales letter follows a time-tested and proven formula: (1) Get his attention, (2) Get him interested in what you can do for him, (3) Make him desire the benefits of your product so badly that his mouth begins to water, and (4) Demand action from him - tell him to send for whatever it is you're selling without delay - any procrastination on his part might cause him to lose out. This is called the "AIDA" formula, and it works.
Sales letters that pull in the most sales are almost always two pages. For the larger priced items, they'll run to at least four pages.
Regardless of the length of your sales letter, it should do one thing, and that's sell, and sell hard! If you intend to close the sale, you've got to do it with your sales letter. You should never be "wishy washy" with your sales letter and expect to close the sale with a color brochure or circular. You do the actual selling and the closing of the sale with your sales letter - any brochure or circular you send along with it will just reinforce what you say in the sales letter.
There's been a great deal of discussion in the past few years regarding just how long a sales letter should be. A lot of people are asking: Will people really take the time to read a long sales letter. The answer is a simple YES. Surveys and tests over the years emphatically prove that longer sales letters pull better than the shorter ones, so don't worry about the length of your sales letter - just make sure that it sells your product for you! The "inside secret" is to make your sales letter so interesting, and "visionary" with the benefits you're offering to the reader, that he can't resist reading it all the way through. You break up the "work" of reading by using short, punchy sentences, underlining important points you're trying to make, with the use of subheadlines, indentations and even the use of another color.
Above all else, you've got to include some sort of ordering method. For online sales, I recommend Paypal, whether you are selling on ebay or on your own website. If by mail order, the order coupon has to be as simple and as easy for the prospect to fill out and return to you as you can possibly make it. Keep the ordering process simple, and you'll find your prospects responding with glee.
For mail orders, should you or shouldn't you include a self addressed envelope? There are a lot of variables as well as pro's and con's to this question, but overall, when you send out a "winning" sales letter to a good quality mailing list, a return envelope will increase your response greatly. On the other hand, pre-stamping is not relevant according to mail order tests which have been performed.
Our recommendation is that you experiment - try it both ways - with different mailings, and decide for yourself from there.