Battery

This game can use up a lot of battery. Try to set your screens brightness to a low setting and use the power savings setting in the game. What this does is it turns your screen to black when the phone is held upside down (i.e. when the phone is in your pocket). The game stays active and the phone vibrates when a pokemon spawns nearby. Watch out however, some people have reported that the game is unresponsive when it ‘wakes up’ and the only remedy is to restart the game and turn this setting off.