AFP Conference Roundup: Best Practices for Annual-Giving Campaigns

"Send that second wave, and you'll be flabbergasted by the results," she said, stressing to make sure that your reply cards are identified as "wave one" and "wave two," etc.

In many cases, it will take four to seven requests before a gift is made, she said. Be creative, with a different look for each mailing. You can use special holidays (like Valentine's Day, Mother's day, Father's day) and occasions ("We've missed you") to try to connect your message with what's going on in donors' lives.