You're managing to get people to your landing page, but they just aren't following through by giving. Here's some help from the Duct Tape Marketing blog: How To Create A High Converting Landing Page.
It's aimed at commercial landing pages, but it's still good advice:
- Unique value proposition in a concise headline
- Image/video showing context of use
- Core benefit statement(s)
- A strong call to action
- Trust elements
- Post-conversion socializing