In direct mail design, copy is king, so maximizing the power of copy to persuade is really important and starts with making it easy to read by following some simple rules.

1. Make the copy very easy to scan to find benefits, desirable information, how to respond, etc. 

2. Break up your copy with subheads, both in the letter and in the brochure.  Make them stand out by using color or bold or underlining them. The more the page is crammed with copy with no visual breaks, the less inviting it will be to the reader.

3. Use fairly wide margins on letters. Use short paragraphs. Think chunks of copy, rather than lengthy paragraphs or long columns. 

4. Use bulleted and numbered lists and other graphical emphasis treatments.

5. Use highly readable, familiar typefaces. Avoid faces that are decorative or hard to read.

6. For letters and brochure copy, use serif faces (e.g., Times Roman). Type size should be 10, 11 or 12 points, depending on the typeface used. Tiny type in body copy challenges older readers, so if that's your demographic, be kind and trend larger, using 11 or 12 point, depending on the typeface. For headlines, use either bold sans serif faces or serif faces - both are readable. To distinguish as a headline, the type must be at least 2 points larger than the body copy type's point size.

7. Start a "swipe file." When you get a direct mail piece you think is good, save it, especially if you've received it several times from an organization that markets a lot by direct mail. That mail piece is probably the one that is winning in their mail tests. Your swipe file can be a great place to look for design tips, ideas, and inspiration.