There are a few things you can do to secure your Gmail account:
1. Use a strong password that is at least 8 characters long and includes a mix of uppercase and lowercase letters, numbers, and symbols.
2. Enable two-step verification for an extra layer of security. With this enabled, you'll need to enter your password as well as a code that's sent to your phone whenever you sign in.
3. Be cautious about the links and attachments you click on in emails, even if they appear to be from someone you know. If you're ever unsure about the legitimacy of an email, contact the person directly to confirm before clicking anything.
4. Keep your software up-to-date by regularly installing security updates for your operating system and other programs, like your web browser.
5. Review Google's Security Checkup tool for additional steps you can take to secure your account.