Recently when Google announced Nexus 7 along with new Android 4.3 Jelly Bean, they also announced that this update will be rolled out for other Nexus devices very soon. If you cant wait for update to be available in your area and want it right now then here is the way.
Disclaimer :- If you are unfamiliar with flashing device then we suggest you not use this technique, if anything happens with you or your device then you and only you will be responsible for it.
Visit this page and download your device update file,
Transfer file to your phone SD Card,
Now boot your device into recovery mode by turning off device then press and hold Volume UP + Power Key and select recovery mode,