Improving sender reputation and inbox placement with Microsoft requires a multifaceted approach centered around understanding and adhering to their unique and stringent email policies. This includes implementing proper email authentication (SPF, DKIM, DMARC), actively monitoring your IP reputation through Microsoft's SNDS and JMRP, and maintaining a high level of email engagement by providing valuable, personalized content. List management practices, such as regularly removing unengaged subscribers and utilizing double opt-in, are also critical. Furthermore, new IP addresses should be warmed up gradually, feedback loops should be established to address complaints, and emails should be thoroughly tested across different clients. Crucially, it's essential to avoid using tools that promise to artificially boost reputation, as Microsoft actively combats these practices and focuses heavily on genuine user engagement and positive interactions with your emails.