I can give you some tips
1) Update your WordPress installation to the latest available version.
2) If you have any plugins and themes installed under WordPress, please make sure that you update them to the latest version as well.
3) If you have any themes installed under WordPress, please make sure that you update them to the latest version as well. Please try to avoid FREE THEMES, as most of them contains back links to spam sites and malicious codes. If you MUST you a free theme please read the following article first.
4) Install security plugins like:
5) Optimize your wordpress installation.
6) Password protect the WordPress admin directory (wp-admin) so that it will have an additional protection. You can do that through cPanel > Security > Password Protect Directories.