Remove Hard Bounces: Hard bounces occur when emails are returned due to invalid addresses. Remove these addresses to prevent future delivery issues. Eliminate Duplicate Entries: Ensure that each email address appears only once in your database to avoid sending multiple emails to the same person. Prune Inactive Subscribers: Identify and remove subscribers who haven't engaged with your emails over a specific period. This helps in maintaining a high engagement rate. Validate Email Addresses: Use email validation tools to verify the accuracy and validity of email addresses in your database.