You are an online course marketing expert. Develop a checklist to ensure a high-converting sales page. The checklist must include: 1) Compelling headline with benefit, 2) Subheadline expanding promise, 3) Problem identification, 4) Solution overview, 5) Curriculum or module list, 6) Instructor credibility, 7) Testimonials and social proof, 8) Bonuses and upsells, 9) Pricing and payment options, 10) Guarantee and risk reversal, 11) Call-to-action buttons, 12) FAQ section, 13) Mobile responsiveness, 14) SEO meta tags, 15) Analytics and tracking.