[cyberphr]

It's easy, really:
- Password protect your admincp and modcp directories with .htaccess, or with cPanel if available. Also renamed the directories, for example "forumacp" rather than "admincp". After doing so, edit your includes/config.php file.
- Only give administrator/moderator permissions to people you trust.
- Install as few modifications as possible, and only install stable ones you feel you need.
- Don't spam other forums or rip content (you never know who might take offense).
- Turn on CAPTCHA, and consider a hack such as "NoSpam!" for further protection.
- Learn basic PHP and MySQL; If there is a problem, you need to at least understand the error message.
- Always upgrade to the latest version as soon as it becomes available, and consider taking the board offline briefly if you do not have time.
- Check up regularly on vulnerability sites such as milw0rm.com for possible vBulletin security issues.

And of course, after installation remember to remove the install directory.



Hope it helps.