1) Location setting
2) DATA+3G
3) Alarm clock
4) Automatic Time Zone Off (because ur phone will try very hard every second to detect ur location so they can provide u time, so just set ur time manually)
5) SIRI
6) Notification (Set it manually, like which only noti you instead of everything, for me i turn off all notification from game and e-mail, i check it manually)
* Notification (What i turn on) : Phone, Message, twitter, LINE and those important only. I dint put fb under it, because human will just check noti from fb randomly and FB is not something that urgent)
7) Adjust your brightness (I use less than 50%, and i dint turn on auto-brightness)

*THE MOST IMPORTANT THING, BEFORE YOU MAKE UR PHONE INTO SLEEP MODE,
MAKE SURE U HAD CLOSE ALL THE UNUSED BACKGROUND RUNNING APPS...*