There are several methods floating around the Interwebthingy, but this is the method that worked first time for me after several other methods failed miserably and no extra software is required.
You'll need these:
- An 8GB (or bigger) USB stick (or an 8GB HFS+ partition on a bootable volume).
- OS X 10.9 Mavericks installer (free download from Mac App Store)
- An admin account
When you download 10.9 Mavericks from the Mac App Store, it will download into the Applications folder. If you leave it there, the installer will delete itself after you install the operating system. If you want to keep it around, you'll need to move it somewhere else. You know what to do.
Now you've put the OS X Mavericks installer somewhere else (let's assume it's on the desktop), and you have a Mac OS X Extended (Journaled)-formatted volume mounted on the system (called "8GB"), you can simply create a Mavericks install drive by typing the following command into the Terminal:
sudo ~/Desktop/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/8GB --applicationpath ~/Desktop/Install\ OS\ X\ Mavericks.app --nointeraction
That's it. It's just one line, and the Installer does the rest.
The command will erase the disk and copy the install files over to the USB stick. It takes a few minutes. The USB stick will have not just the OS X installer, but also an external recovery partition that has Disk Utility on it.
One more thing... now that you have your shiny new USB installer all ready to go, put it in a drawer and forget all about it. Don't bother to get it out until after some major updates to 10.9 have been released, and install from that version instead. Maverick 10.9.0 is just not ready for prime time. We've already bricked a MacBook Pro with it.
Edit: It looks like 10.9.2 is finally going to work. That's your baseline.