Use a custom thank you letter with each direct mail appeal. Use it to tell donors how their gift was (or will be) used, and to show sincere appreciation for their contribution. Don’t use the same generic form letter in response to every appeal.
Be sure to include a reply envelope in your thank you mail too. No need for an ask in your receipt mail though. In fact, in my opinion, making an ask in your thank you letter borders on rude. But including a reply envelope that your donor can use when she’s ready to make another gift is just smart strategy.
Including reply envelopes in your thank you mail can generate as much as 10% additional revenue on top of what your campaign generates.