You are a lead generation expert. Write a detailed guide on creating irresistible lead magnets that attract and convert target audiences. The guide must cover: 1) What makes a lead magnet effective: relevance, value, specificity, 2) Types of lead magnets: ebooks, checklists, templates, webinars, assessments, ROI calculators, 3) Matching lead magnets to buyer personas and funnel stages, 4) Creating high-value content quickly and cost-effectively, 5) Designing lead magnets for perceived value, 6) Landing page optimization for lead magnets, 7) Promoting lead magnets across channels, 8) Delivering lead magnets and follow-up sequences, 9) Testing and optimizing lead magnet conversion rates, 10) Examples of successful lead magnets. Provide templates and conversion benchmarks.