1. Enable usb debugging in Android. (I am using kitkat)

2. connect phone with usb. In notification you will see: "USb Debugging Connected".

3. Open terminal and run:

adb devices
# you will see devices list

------ start output ------
List of devices attached
* daemon not running; starting now at tcp:5037
* daemon started successfully
0123456789ABCDEF device
------ end output ------

1. Then run: (it can take half minutes)

$ adb tcpip 5555

------ start output ------
restarting in TCP mode port: 5555
------ end output ------

After showing this message terminal will be active. Active means, terminal is ready to take another command.

Note: if this command is stuck. Run "$ adb kill-server" and try "step 4"

1. Disconnect USB

2. Go to the Settings -> About phone -> Status to view the IP address of your phone.

3. Then run:
   $ adb connect

   suppose I run: "$ adb connect 192.168.0.101"

------ start output ------
connected to 192.168.0.101:5555
------ end output ------

Note: If it does not work, you can try with port number: "$ adb connect 192.168.0.101:5555"

1. Now you check the connected devices, run: $ adb devices

------ start output ------
List of devices attached
192.168.0.101:5555 connecting
------ end output ------

Note: if you see connecting like me, try "step 9"

1. In android phone,
2. Turn off usb debugging, and then turn on usb debugging. or, turning off and on Developer's Option again from Settings
3. Then run: "$ adb connect "
4. Then run: "$ adb devices" Now you should see,

------ start output ------
List of devices attached
192.168.0.101:5555 device
------ end output ------

Special Note: Still you need to enable "USB DEBUGGING" to debug over WIFI