Improving a bad domain reputation involves a comprehensive, multi-faceted strategy. The core steps include identifying and rectifying the 'bad thing' that caused the initial damage, and then actively working to send mail that recipients want to receive. Authentication (SPF, DKIM, DMARC), regular list cleaning, engaging content, targeted segmentation, complaint feedback loop monitoring, bounce rate management, and deliverability testing are all vital. Employing double opt-in for new subscribers, providing easy unsubscribe options, personalization, and potentially utilizing a dedicated IP address for larger sending volumes are also recommended. Consistent effort, adaptation to recipient feedback, and utilization of monitoring tools like Google Postmaster Tools and Microsoft SNDS are crucial for long-term improvement.