Security is a Process, not a Product. It's an ongoing process for any product or service. As we know Internet is full of spammers and hackers threatening to deface or take down your site or steal confidential data. Everyone should keep security concern in mind when administering site/blog. No doubt Drupal community has developed a solid process to help you avoid major headaches when dealing with security matters.
Sharing Few major thing to make it more secure .
Use Strong Passwords