1-you can change default admin login page address
2-change admin username
3-update your wordpress and plugins
4-backup your site regularly
5-Disable File Editing
You can easily do this by adding the following code in your wp-config.php file.
// Disallow file edit
define( 'DISALLOW_FILE_EDIT', true );
6-Disable PHP File Execution in Certain WordPress Directories
edit your htaccess and add
<Files *.php>
deny from all
7-Limit Login Attempts
8-Change WordPress Database Prefix
9-Disable Directory Indexing and Browsing
you need to add the following line at the end of the .htaccess file:
Options -Indexes
10-Disable XML-RPC in WordPress
11-Automatically log out Idle Users in WordPress
12-Add Security Questions to WordPress Login Screen
13-Add Two Factor Authentication:https://wordpress.org/plugins/two-factor-authentication/
for doing all that mentioned above you can simply install this plugin and do what it says:
https://wordpress.org/plugins/all-in-one-wp-security-and-firewall/