If you are using Android Studio as your test device you may run into the problem of your device not showing up on the emulator list when you need to test your app. I had that problem. Well this worked for me.
1. Clear your phone debug permissions tapping on "Revoke USB debugging authorizations"
2. Install the LG mobile drivers from LG http://tool.xcdn.gdms.lge.com/dn/downloader.dev?fileKey=UW00120120425
3. Plug your phone to your laptop, authorise the phone to be used as a debug device and prosper