WugFresh one of the popular Rootkit developers has posted a guide with 3 options for installing an OTA, including the advantages and disadvantages of each option. Even if you prefer to wait on the OTA from Google, the discussion provides some valuable information for the rooted and non-rooted user, when an OTA installation goes unexpectedly.
Just tap the link following the screen shot.
http://www.wugfresh.com/faqs/how-to-update-ota-not-working/Sent from my Nexus 7 using Tapatalk