1. Connect through USB
  2. adb devices
  3. adb tcpip 5555
  4. Disconnect from USB, and find IP_address of the Android device
  5. adb connect IP_address:5555
    e.g. adb connect 192.168.1.100:5555
  6. adb devices, and the devices shows as e.g. 192.168.1.100:5555