You are an education and email marketing expert. Write a detailed, 2400-word guide on email for daycares. The guide must cover: 1) Building an email list of parents, 2) Welcome sequences for new families, 3) Daily updates and newsletters, 4) Event and activity announcements, 5) Educational content for parents, 6) Enrollment and registration emails, 7) Referral request emails, 8) Seasonal and holiday campaigns, 9) Re-engagement for past families, 10) Metrics for daycares (enrollment).