To protect online accounts from being accessed through a compromised email address:
- Set up 2-factor authentication.
- Set up two-step verification for services if it is available.
- Choose a unique, complex and difficult-to-guess password.
- Change the password periodically.
- Set up a unique security question for each account.
- Do not use the same password across multiple sites.
- Do not open suspicious links or email attachments
- Keep an eye on account activities.
- Do not share the passwords with anyone.