Earlier today, the Android 4.3 source code and Nexus factory images became available for download. Google also announced that the supported Nexus devices would start receiving their over-the-air updates soon. If you can’t wait, and I can’t blame you, it’s very easy to install Android 4.3 on your favorite (supported) Nexus phone or tablet. Especially if you’re used to flashing custom ROMs.
Right now, Android 4.3 is available for the GSM and Play Store Galaxy Nexus, Nexus 4, Nexus 7, and Nexus 10.
WARNING: By not waiting for an official OTA update, you’ll be wiping your device, losing all of your apps and app data. The following steps assume you have working ADB, fastboot, and an unlocked bootloader. You may need to install the Android SDK. If you are not familiar with these terms, proceed at your own risk. Android Authority will not be held responsible for broken devices.
When you’re done, you should have something like this if you’re on a Nexus 7. Enjoy.