Building a network through email marketing involves several strategic steps. Firstly, you need to grow your email list by offering incentives such as exclusive content, discounts, or free trials. Secondly, segment your email list to tailor your communication to different audience groups. Personalization is key - use the recipient's name, understand their preferences, and send them relevant content. Additionally, engage with your subscribers through interactive content like surveys and polls, and encourage them to share your emails with their network.