What best practices does Microsoft recommend for maintaining email hygiene?

Large senders should implement the best practices to ensure their messages are trusted and delivered reliably. Following are some of the best practices to ensure email deliverability:

• Compliant P2 (Primary) Sender Addresses: Ensure the From or Reply‐To address is valid, reflects the true sending domain, and can receive replies. 
• Functional Unsubscribe Links: Provide an easy, clearly visible way for recipients to opt out of further messages, particularly for marketing or bulk mail. 
• List Hygiene & Bounce Management: Remove invalid addresses regularly to reduce spam complaints, bounces, and wasted messages. 
• Transparent Mailing Practices: Use accurate subject lines, avoid deceptive headers, and ensure your recipients have consented to receive your messages.