1. Clear Cache
2. Factory Reset
3. Opt out of all background reporting to Google and Samsung. (Google Location is okay)
4. Don't update any of the pre-installed apps through the play store that your not going to use.
5. Turn off auto update in the pay store.
6. Disable any app you don't want in the application settings.
7. Set location settings to GPS only.
8. Set WiFi to sleep when the screen is off or stay awake only when charging.
9. Turn off WiFi and Bluetooth scanning.
Last but not least DO NOT use an SD card unless your phone doesn't have the ejection bug. Every time you see the SD notification your phone is scanning the SD card. This can use a lot of power in the background as it wakes up the phone and doesn't allow it to go into its deep sleep state.
Also make sure you set it up as a new device instead of copying information from an old phone.
(Some are also reporting an improvement by just turning off Google and Samsung background reporting without even doing a factory reset.)
(Also DO NOT disable any packages using a package disabler app) Just disable apps you don't want through the application settings. I along with many others have reported worse battery life after disabling some of the packages.
For those of you (1 of you) saying this is pure snake oil, the following screenshots make for some compelling proof that it is not.
The first set of screenshots are of my battery performance before taking these steps and then some screenshots after taking these steps.