Clearly communicate the impact of small donations: Make sure potential donors understand the impact that their spare change can have when they're combined with the donations of others.

Make it easy for donors to sign up: Provide clear instructions for how to join the round-up program, and make it as easy as possible for donors to opt in.

Share stories of impact: Share stories of how the round-up program has made a difference in the past, or how it is currently helping to achieve your organization's mission. This can help potential donors see the concrete impact of their contributions.

Offer incentives: Consider offering incentives to donors who join the round-up program, such as recognition on your organization's website or social media channels, or special updates on the impact of their donations.

Promote the program through multiple channels: Make sure to promote the round-up program through a variety of channels, including social media, email, and your organization's website. This will help ensure that as many potential donors as possible see the opportunity to join.

Follow up with donors: After someone has signed up for the round-up program, make sure to follow up with them to thank them for their support and to provide updates on the impact of their donations. This can help build trust and encourage them to continue supporting your organization through the round-up program.