This note works for Windows (e.g. Windows 7, Windows 8, …), Linux … ISO image only, and all commands in Terminal.

If you’re interested in using Disk Utility, try this: Create OS X Mavericks Bootable USB Drive from AppStore Release, but DON’T forget to unmount partitions.

To launch a Terminal, simply open Spotlight and type Terminal, in most cases, you can see Terminal listed after ‘Ter‘.

For Windows 7/8 or later, Boot Camp Assistant is the BEST tool.
In ‘Select Tasks‘, CHECK ‘Create a Windows 7 or later version disk’ and UNCHECK all others.
In ‘Create Bootable USB Drive for Windows Installation‘, choose the right usb destination disk.