I would begin by listening to the podcast they are full of great tips for direct mail. Also I would be more concerned with how consistent and persistent you are over what you drop in the mail box.
@Brandon Joynersome important aspects of direct mail success:
- send multiple times to same addy
- change up the mail piece so it appeals to different people (i.e. yellow letter, postcard, image, copy heavy, etc.)
- focus on the recipent's needs over your needs - for example, it's better to say "Here are 10 Ways to Stop Forclosure" vs. "I Want to Buy Your House for Cash" as long as your 10 Ways has how they can contact you - educate them vs. do a hard sell