When you create a website you spend lot of time and effort in creating it.It would be very bad if the site got hacked.here now i am going to tell you how make your drupal site secure.
First of all install security review module from drupal.org.
This module runs various checks which helps you to know if all things are configured for your site correctly or not.By this module you get a checklist of errors by the help of this you can take steps to rectify the errors.