How can I increase my pay-it-forward donations

There are a few ways:

Relaunch in an email: if you have an email newsletter or email customer base encourage them to get involved and educate them on how it works again in an email. Check out this link for tips/content/advice
Use social media: educate your customers in social media. Use our content and follow our guides in your admin dashboard
Run a campaign: integrate pay-it-forwards into a campaign. For example, enter all customers who pay-it-forward into a draw to win a prize over a given time period.