Applications (such as Skype™) that frequently utilize VOIP (Voice over IP) and other data via Wi-Fi or 3G/4G can significantly reduce battery life. Disable any such applications when maximum battery life is desired.
Set the display sleep to a start after 15 seconds of inactivity. To change the display timeout settings: from the home screen tap > Settings > Display >Advanced > Sleep > select a shorter delay time.
Reduce the intensity of the display. To change the display's brightness, Settings > Display > Brightness level > drag the control bar to the left for a dimmer display or right for a brighter display.
Disable Wi-Fi when not using it. To disable Wi-Fi: Settings > Network and Internet > tap the on/off button so it is no longer green.
Make sure your phone has the latest software updates. To check for the latest updates: Settings > System > System update > Check for update.
Stop any unnecessary programs you installed from running in the background by: Settings > Apps and notifications > See all apps > select and disable any apps that you do not need.
Note! Only stop applications that you have installed. Stopping other pre-installed applications may result in poor phone performance or errors.