During a reboot,I put the settings app on my first Jellybean screen (while rebooting, it was easier to get to). Then, go activate Developer mode, then put on USB debugging, and plug phone in... Mine was a little jinky, so I had to take USB out a few times, try to enable... what you are looking for is a prompt that says Allow this computer (type of thing).
I can't get adb no matter what I try :'(
I have tried every connection mode and every USB port and windows and Linux developer mode on and off but other than charging nothing happens...
one second while I wipe my tears.
-boxorandyos
<sent from my nexus4>