There’s many ways to do that, you can change the permalink to your login page, choose a strong password, delete the default “Admin” user, Password Protect wp-login.php and one of my favorite is to add Two Factor Authentication.
The Authy Two Factor Authentication for WordPress Plugin add a second layer of security onto your WordPress login page, so when you submit your username and password, you will get notified on your mobile device to enter your Two Factor Authentication token.
You can also use Authy Chrome extension to run Authy on your desktop, Whether you are using Mac, Linux or Windows.
In the settings of the Authy Plugin, you will be able to set who uses Two Factor Authentication, for Administrator, Editor, Author, Contributor, Subscriber and the ability to “Disable external apps that don’t support Two-factor Authentication”.
And that’s it, download it, activate it and you are good to go with a more secure site that is harder to breach.