To save battery:
  • Don't use 3G network
  • Don't change CPU freq
  • Don't use live wallpapers
  • Use conservative governor if you use your phone for calls only
To play recorded videos:
  • Use an external player supports Mp4 encoding like MX player
Reboot phone:
  • After using Wi-Fi tethering (has reboot issue)
Use HWA Settings app:
  • To disable/enable hardware acceleration for gmail, facebook and other apps (fixes white screen issue)