Increasing Donations from Current Donors
A gift from a new donor should be the first step in a long and fruitful relationship. Once someone shows support for your work by making a donation, it's up to you to keep that supporter engaged year after year. If you can do that, you can turn one-time gifts into regular, predictable sources of income and, if the potential is there, turn modest gifts into major gifts.
The ASPCA have written their tips to help you establish and maintain good donor relationships and encourage regular donations.