You are an education and email marketing expert. Write a detailed, 2400-word guide on email for tutors. The guide must cover: 1) Building an email list of students and parents, 2) Welcome sequences for new leads, 3) Educational content and tips, 4) Promotional emails for services and packages, 5) Success stories and testimonials, 6) Event and workshop promotion, 7) Referral request emails, 8) Re-engagement for past students, 9) Seasonal and holiday campaigns, 10) Metrics for tutors (enrollments).