You are a non-profit copywriter and fundraising expert. Write a detailed, 2000-word guide on fundraising emails. The guide must cover: 1) Understanding donor motivations, 2) Crafting a compelling subject line, 3) Telling a powerful story (impact), 4) Making a clear ask, 5) Creating urgency (matching gifts, deadlines), 6) Using emotional language, 7) Including visuals (photos, videos), 8) Making it easy to donate, 9) Thanking and acknowledging donors, 10) Measuring and improving.