+ Blog Hecking +

the best way to protect one's blog against hacking

First of all make sure that you have a strong password that no one can guess easily.
Also, some Add-On's and Widgets are not trusted, they can bring you Advertisements and steal your account credentials (user name and password), especially those free Toolbars and the untrusted programs that people add to their browsers.
Make sure you have the latest Antivirus in order to protect yourself from key-loggers and the other Malwares.
Sometimes Antiviruses cannot protect you from every single Malware, so having a personal Firewall as an extra layer of security can block those softwares from contacting their original servers back.