Now that you finally have your shiny new Nexus 7 the first thing you may want to do is Root it! That is normally the first thing I do with all of my devices. In this instance you will want to unlock the bootloader first then you can proceed to rooting your device. Why root a stock android device you ask? There are all kinds of awesome things you can do with a rooted device. You can backup your entire system with apps like Titanium Backup, you can install all kinds of mods with apps like Xposed Framework, and the list goes on and on. The method for rooting is pretty simple. Follow the quick guide below!
Step 1: unlock the bootloader
Step 2: Download the TWRP image to your PC (place in same folder you have your fastboot and adb files), Download the SuperSU.zip and place on the Nexus 7's internal memory
Step 3: Boot Nexus 7 into bootloader (from powered off hold power+volumeup+volumedown)
Step 4: Open command line from the folder where you have the TWRP image (easiest way is to navigate to that folder, shift+rightclick, open command line here)
Step 5: type command "fastboot flash recovery filename.img"
Step 6: reboot into recovery by entering the command "adb reboot recovery"
Step 7: Flash the SuperSu
Step 8: Profit!
Via Android Police