-Turn off background Tasks you don't need ( be reminded Notifications won't work if you do so )
-Delete Skype. ( Don't disable it, f**** delete it )
-make sure your brightness on AUTO, or even better at low
-Location services OFF
-Email account syncing to manual or hourly for accounts that don't require immediate attention. Same goes for calendars.
-Go to your MS account, make sure no services have access to your account, such as twitter or Google.
-Battery saver.
That should do it.