Here are my useful tips to prevent WordPress from hackers.

1. Update WordPress, Theme, and Plugin regularly.
2. Choose a secure web hosting with the latest PHP and MySQL.
3. Use secure passwords.
4. Use themes and plugins only from trustable company.
5. Install security plugins.
6. Use reCAPTCHA.
7. Install SSL Certificate. (SSL is short for Secure socket layer)
8. Select a hosting provider with automated backup; nevertheless, you must backup your own WordPress website regularly.