You are a professional services and email marketing expert. Write a detailed, 2400-word guide on email for architects. The guide must cover: 1) Building an email list of potential clients, 2) Lead magnets (project portfolios, design guides), 3) Welcome sequences for new leads, 4) Showcasing projects and case studies, 5) Educational content on design trends, 6) Newsletters with firm updates, 7) Event and webinar promotion, 8) Client appreciation and referral, 9) Metrics for architects (project inquiries), 10) Visual design of emails.