Easier Said Than Done: Secrets for Maximizing Your Net Revenue

To wisely send less mail, put these two facts to work for you: Segment your donor base by recency and gift amount; then trim segments that have given less recently and give lower amounts.

Just ask
Here's the coolest move in the business: If you ask donors how often they want you to contact them, they will become more responsive. You're probably thinking I left something out of that last sentence. I didn't. Just asking them what they want you to do improves their responsiveness.