Create your mailer in a graphic design layout program, such as Adobe InDesign, QuarkXPress or Adobe Illustrator. Settle on two or three colors, total, for your mailer.
Decide on a final size for your mailer. Make that decision depending on the amount of information you want to print in the advertisement. Common sizes for mailers include 8.5 by 11 and four by six inches. You can also fold a large-sized mailer in half and seal it before mailing.
Use black for the text (except the headline). Choose one or two photos related to your product or service to add to the mailer and place them either to the left or right of any text you add to the piece.
List your business information at the top of the mailer so that the recipient immediately knows the name of your company. Designate an area of the mailer for your return address, stamp and the address of your recipient, as well.
Print your main advertising slogan, headline or motto prominently near the top of the mailer in large lettering. Use a bold colorful font consistent with your company colors.
List the benefits of the product or service you offer under your main headline or saying in a bullet-point format. Possible benefits could include "saves you money" or "makes you faster." Provide more details about the features of your offering next in a short paragraph under the list of benefits.
List your contact information (such as a website address or phone number) near the bottom of the mailer prominently, again with bold text.
Add additional items to the mailer as you see fit. For instance, you might want to include testimonials from previous clients under your photos or after your description of services.