How to enable USB debugging in Android?

How do you enable USB debugging in the Nexus 7 (first generation)?

Edit: The accepted answer applies to other android devices also where Developer option is hidden .

Toggle on "USB Debugging" in the "Developer Options" area of Settings.

If you do not see "Developer Options", go into "About device" in Settings and tap on the "Build number" entry seven times, which will unlock "Developer Options".

As documented on Android Developers: https://developer.android.com/training/basics/firstapp/running-app.html

do this

1) go to settings

2) go to developers setting

3) enable developers setting by turning the switch on top of the page.

4) select Usb Debugging.

Note: if developer option is not available then Tap 7 times on the build version button to unlock developer options...

First of all, you have to check Do you have unlocked developer option or not? If not then you can unlock it by clicking on "Build number" 7 times where you can found this "Build number" option in Setting -> About Phone

After then open Developer option which is available second last option in setting page. Check in Usb Debuging. you will get dialog which show you approvance for Usb debuging for separate computer.

Steps For Usb Debuging

1. Open setting in Phone

2. Open Developer Option

3. Enable developers Option by Clicking 7 times on "Build Number"

4. Check Usb Debugging.