[Galaxy S II Android Development] voku1987:
this would be as if you want to buy as much as possible with minimal costs ... it only work if Dorimanx send you some gifts ;) but most of the settings from ExTweaks-App can reduce performance & increase battery life or conversely. e.g.: if you increase GPU frequency (MHz) and reduce GPU voltage level (mV) then your device will die ...

save battery:

1.) "Tweak your display settings"

try lowering the brightness of your phone (turn off automatic brightness as well)

reduce the time until the screen turns off when not in use

use a dark wallpaper (theme, bgoog.com, etc.)

disable animated wallpaper

Tip: you can see in settings -> battery -> how much battery-power your screen/apps consumed

2.) "Turn off wireless services you don’t need"

do you really need Bluetooth, WiFi, GPS, 3G and more -> turning off some of these when you don’t need them

Tip: you can quickly toggle these settings on/off by using Android’s built-in power widget or use a app from market for that :)

3.) "Tone down data usage"

use only 2G networks -> 2G networks are noticeably slower than 3G, but 3G uses more power

try to use WiFi whenever possible instead of 3G as well

disable global autosync (background update from App like facebook, twitter etc.)

disable app autosync (some apps have their own sync schedule, so take a look at the settings from your apps and don't install to much apps)

less frequently autosync (if a app e.g. email-app need background-sync, then use less frequently autosync

put your phone on "airplane mode" when you are not using it e.g. at a meeting

4.) "Don't use much [background] apps (widgets)"

try e.g. "OS Monitor"-App to see how much resources your running Apps consume! (CPU usage = battery usage)

try e.g. "Autorun Manager"-App to prevent some auto-starts ;)

disable home screen widgets that are pulling data from the web & you don’t need

do not leave applications running when you don't need them

uninstall total unused apps

5.) "Don’t use task killers (in the most cases)"

the System will kill Apps automatically you don't need a Task-Killer-App ... some of this Apps consume even more power because those apps usually start themselves up again right after you kill them and so they need cpu & drain power again ...

activate "close app when back button is pressed" in the settings (only CM?)

6.) "Automate your power conservation"

easy to use: Juice Defender

most customizable: Tasker

Note: this Apps also running in background and need battery-power, so if you use "power widget" manually you maybe don't need such Apps

7.) "change Kernel & root-settings"

use the battery-profile (you can switch it via recovery)

use e.g. "CPU Spy"-App to see how long the cpu usage it's frequencies (+deep sleep)

disable Ads via hosts-file (disable loading of images etc. on website & in apps)

if you don't need more free memory -> don't use zram -> compress / decompress memory in memory (more cpu usage = more battery usage)

use e.g. "conservative" (+ extra settings) as cpu-scheduler via "ExTweaks"-App and check the effect e.g. with "SetCPU"-App

reduce (max.) cpu speed via "ExTweaks"-App -> "CPU"

reduce "touch screen lock freq" via "ExTweaks"-App -> "SCREEN"

use cpu undervolting (can cause SOD) via "ExTweaks"-App -> "CPU"

disable BLN (Back Light Notification) via "ExTweaks"-App -> "BLN"

- disable "led-on-touch" (& reduce led voltage level) via "ExTweaks"-App -> "BLN"