[AT&T, Rogers, Bell, Telus Samsung Galaxy S III] RJQXCV:
This is my all inclusive guide on how to get the most out of your battery without sacrificing functionality. Specially tailored for the i747.

WARNING: I ASSUME NO RESPONSIBILITY FOR ANYTHING YOU DO TO YOUR PHONE. PROCEED AT YOUR OWN RISK.

!!!NANDROID BACKUP!!!​

This guide assumes that you're running Cyanogenmod 11 or a custom ROM based on it. It is organized from most practical and user friendly, to more technical and intensive.

The first manner of business is to upload to the latest bootloader/modem, which can be found here: http://invisiblek.org/d2firmware.html

This provides the most stability/support for the latest CM Nightlies.

Simply download the .zip and flash it in your recovery of choice.

Go into "Settings" > "Apps" and delete any apps you don't use anymore.

Go into all apps you DO use, and make sure "Location" and "Notification" settings are either OFF or on according to if you need them or not.

Disable "syncing" in weather apps, news apps, and any other apps that have background syncing enabled.

Disable "WiFi" when not in use.

Disable "Data" when not in use.

Disable "Location" when not in use. (THIS INCLUDES LOCATION REPORTING.)

Disable "Bluetooth" when not in use.

Disable "NFC" when not in use.

Disable "Automatic Backlight"

Manually set brightness to lowest setting.

Set Screen Timeout to 1 minute or less.

Disable "Sync" when not necessary.

Disable "Auto Rotation" when not necessary.

Disable all haptic/sound feedback under "Sound."

Go into "WiFi" settings, press your menu key, and press "Advanced." Be sure that "Scanning always available" is unchecked.

CHARGE YOUR PHONE WHENEVER POSSIBLE.

Download "Greenify" from the Play Store, open it up, and start hibernating every app you don't depend on. DO NOT HIBERNATE MESSAGING APPS.

I personally hibernated every non-system app I had excluding "Google Keyboard."

You have a special feature called "App Ops under your "Privacy" settings.

Press "Privacy Guard." You'll be presented with a list of apps. These apps can be "secured" with a click. Simply press and app you don't want accessing your location settings, and the little grey lock to the right of the app will become white. This will disable the app from using location services.

Third, open up your apps list under Settings > Apps > "All" tab. Cyanogenmod has many apps that the typical user doesn't want/need, and that take up precious RAM and CPU cycles.

You can disable system apps by clicking on them, and then "Disable."

Apps that can be safely disabled include:

Android Keyboard – REPLACE WITH GOOGLE KEYBOARD

Android Live Wallpapers

Basic Daydreams

Black Hole

Browser – REPLACE WITH CHROME BETA

Bubbles

CM Updater

CM Wallpapers

com.android.wallpaper.holospiral

Downloads

Email – Up to you.

Exchange Services – Safe to disable only if you disable Email

Face Unlock

Gallery – REPLACE WITH QUICKPIC

Google Backup Transport – ONLY IF YOU DON'T USE GOOGLE BACKUP

Google One Time Init

Google Partner Setup

Google Text-to-speech Engine – AT YOUR OWN DISCRETION

Magic Smoke Wallpapers

Market Feedback Agent – DISABLES... MARKET FEEDBACK...

Movie Studio

Music Visualization Wallpapers

Phase Beam

Photo Screensavers

Pico TTS - AT YOUR OWN DISCRETION

Setup Wizard

Tags - ???

Terminal Emulator

Themes provider – STUCK W/ DEFAULT THEME

Voice Dialer

I have disabled all of these apps and had no ill consequence. I haven't gone as far as uninstalling them, but you may if you wish.

Download KT's latest kernel from http://xdaforums.com/showthread.php?t=1756776

Flash in recovery. Be sure to wipe Cache and Dalvik before and after!

WHAT YOU DECIDE TO DO WITH THIS KERNEL IS UP TO YOU. YMMV.

Open KTweaker app.

Set governor to "pegasusq" - This is a more conservative governor, and also allows hotplugging.

Undervolt CPU by 75 mV across the board. - YMMV.

Undervolt GPU by 50 mV across the board. - YMMV.

Set GPU Governor to "simple."

Set "Set options on boot" to set with a 20 second delay. (In case something goes awry.)

Reboot.

ETC. TIPS:

- Get any widgets you don't use off your Launcher. They eat battery too.

- Don't use custom launchers with riced out animations. This tears up your GPU, and your battery life will suffer as a result.

- Turn off "Mock Location" in Developer Options.

- DO NOT USE TASK KILLERS!!!

- Disable "Automatic home clock" in the stock "Clock" app.

- Use ART!

- Turn off roaming!

I'm sure I'm forgetting something. I'll update this if I remember anything. Let me know if this has helped you at all. Feel free to add any tips as you see fit.

Give me a thanks if I've helped you out!