From npENGAGE, a quick check-up for a solid, functioning website: 10 Must-Have Elements for Nonprofit Websites. Make sure you have these things:
- Contact page
- "About us" section
- Information for donors
- Online donations system
- Blog
- Photos and portfolio
- Social media widget
- Testimonials
- Volunteer or career opportunities
- Newsletter signup
(I'm not sold on the need for a blog. That may not be worth the trouble for everyone.)