When you encourage prospects to act now instead of later, response rates increase.

1. One way to do this is to put a deadline on your offer.

Since 3rd-class mail takes an average of 2½ weeks to be delivered nationwide, make the deadline at least 8 to 12 weeks from the mail drop date. Alternatively, for any mailing that goes out September or later, a good deadline date is December 21.

Copywriter David Yale recommends emphasizing that the deadline date is final by adding the phrase “it’s too late” as follows: “This offer expires December 21, 2010. After that, it’s too late.”

For e-mail marketing, you can say the offer is good only if the recipient replies “today” or “this week”.

2. If you are not comfortable putting a deadline date on your mail piece, specify a time frame within which the reader must reply, e.g., “reply within the next 10 days”.

3. Or at least make it clear that this is a time-limited offer. Copywriter Milt Pierce suggests this wording: “But I urge you to hurry. This offer is for a limited time only. And once it expires, it may never be repeated again.”