You are a freelance business coach and email marketing expert. Write a detailed, 2400-word guide on email for freelancers. The guide must cover: 1) Building an email list from your network, 2) Welcome sequences for potential clients, 3) Nurturing leads with value, 4) Showcasing portfolio and case studies, 5) Promoting services and packages, 6) Client appreciation and referral requests, 7) Staying top-of-mind with newsletters, 8) Re-engaging past clients, 9) Tools and platforms for freelancers, 10) Metrics and time management.