If you are one of them that rarely uses Bluetooth. Deactivate it. It will save you about 1 hours of battery. Go to Bluetooth.
Siri is fun and an useful tool I you use her often. But if you don't use her. Then turn her off. Go to general - Siri.
Vibrate on ring and silent isn't something you should use if you wants to have a longer battery life. Just turn them off. Go to sounds.
Using auto-brightness isn't that smart. Just deactivate it and set it manually. Go to brightness and wallpaper.
iCloud is very clever but do you need to sync all of your things? The answer is no. So turn off, all the things you can live without. Go to iCloud.
Turn off setting time zone. Go to privacy - location services - system services. And a bonus tip. If you think your App Store is slow then turn off genius for apps.
And the final tip is. Close down all the apps in multitasking, by double tapping the home button.