Optimizing email deliverability ensures that your emails reach your subscribers' inboxes rather than their spam folders. Key strategies include maintaining a clean email list by regularly removing inactive subscribers, using a reputable email service provider (ESP), authenticating your emails with SPF, DKIM, and DMARC, and avoiding spammy words and phrases in your subject lines and content. Monitoring your sender reputation and engagement metrics also plays a significant role in deliverability.