Are you crazy? 6 hours of screen on time is super amazing- you've got an awesome battery. If you are looking to extend your battery life even further then I suggest rooting your phone (if you haven't already done) and use greenify. Other than that, just turn your brightness down and manage your radios efficiently. As far as I can see you have amazing battery life. Do you game or do you just tend to go on YouTube, reply to texts etc...?