[Optimus L3, L5, L7 General] f3tus:
(i) Slimming your ROM:

Original thread by darknessx10: http://xdaforums.com/showthread.php?t=2387429

Remove (either from the ROM/Gapps zip before you flash, or after with a file manager, but don't forget to reboot):

/system/tts

/system/fonts/*.ttf (remove all unnecessary fonts that you don't use (see thread linked above))

/system/media/video (useless)

/system/media/audio/alarms (I use a custom song)

/system/media/audio/notifications (just leave one that you use, I use Argon.ogg, or delete all if you use a custom one)

/system/media/audio/ringtones (I use custom songs)

/system/usr/srec/config (offline Google Now - useless)

/system/lib/*.so (remove all unnecessary Google libraries that you don't use, for example, these are safe to remove):

libfilterpack_facedetect.so (Face unlock, useless)
libflint_engine_jni_api.so (Google TTS)
libfrsdk.so (Face unlock, 1.8 MB)
libgcomm_jni.so (obsolete Google+ library, 7-8 MB)
libgoogle_recognizer_jni.so (Google Now, 7-9 MB)
libgoogle_recognizer_jni_l.so (Google Now, 9 MB)
libgtalk_jni.so (Google Talk, 4 MB)
libgtalk_stabilize.so (Google Talk)
libjni_latinime.so (LatinIME, only remove if you use another keyboard app)
libmicrobes_jni.so (Microbes wallpaper)
libnfc.so (only delete if you don't use NFC)
libnfc_jni.so (only delete if you don't use NFC)
libnfc_ndef.so (only delete if you don't use NFC)
libpicowrapper.so (Pico TTS)
libplus_jni_v8.so (Google+)
libspeexresampler.so (Google TTS)
libspeexwrapper.so (Google TTS)
libttscompat.so (Pico TTS)
libttspico.so (Pico TTS)
libvideochat_jni.so (Google Talk, 4 MB)
libvideochat_stabilize.so (Google Talk)
libvorbisencoder.so (Google Ears)

/system/app/*.apk (remove all unnecessary apps that you don't use, for example, these are safe to remove):

Apollo.apk
BasicDreams.apk
CellBroadcastReceiver.apk
ChromeBookmarksSyncAdapter.apk
CMAccount.apk
CMFileManager.apk (I use Root Explorer)
CMWallpapers.apk
DrmProvider.apk (leave if you have DRM-protected songs/videos)
DSPManager.apk
Email2.apk (I use Outlook app)
Exchange2.apk (unless you need Exchange Services for email)
FaceLock.apk
Galaxy4.apk
GenieWidget.apk
Gmail.apk
GoogleBackupTransport.apk
GoogleEars.apk
GoogleFeedback.apk
(Google)OneTimeInitializer.apk (runs one time after flashing gapps, safe to remove after)
GooglePartnerSetup.apk (do not remove if you have a credit card linked to your Play store)
GooglePlus.apk
GoogleTTS.apk
HoloSpiralWallpaper.apk
HTMLViewer.apk
LatinIME.apk (do NOT remove unless you have another keyboard app (I use Kii))
LatinImeDictionaryPack.apk
LiveWallpapers.apk
LiveWallpapersPicker.apk
MagicSmokeWallpapers.apk
Microbes.apk
Nfc.apk (if you don't use NFC)
NoiseField.apk
PhaseBeam.apk
PhotoTable.apk
PicoTts.apk
QuickSearchBox.apk (remove if you don't use the Google search widget in the homescreen)
SetupWizard.apk (do not remove if you have not setup your phone yet (account, language, time, etc.))
SoundRecorder.apk
SpeechRecorder.apk
Stk.apk
Tag.apk (if you don't use NFC)
Talk.apk
Talkback.apk
ThemeChooser.apk (I don't use themes)
ThemeManager.apk (I don't use themes)
Thinkfree.apk
Torch.apk
Trebuchet.apk (do NOT remove if you don't have another launcher app)
UserDictionaryProvider.apk
VisualizationWallpapers.apk
VoiceDialer.apk
VoicePlus.apk
VoiceSearchStub.apk
VpnDialogs.apk (unless you use VPN)

ROM and /system will be 85 MB+/- lighter.

See a description of most CM/Google apps here, otherwise google for more information.

If you are not using CM, you have other stock apps. Google them to see if they are okay to delete.

Extra: After every reboot, there are some useless Google services running in the background. Go to Manage apps and select Running apps. For me they are Google Play services and Google Play Store. Click them and stop PendingNotificationsService, GoogleLocationManagerService, NetworkLocationService, NlpLocationReceiverService and AnalyticsService. GPS and Play Store will still work normally and notify you of updates, etc. They seem to re-start themselves every so often, too... If you don't want to do it manually and disable them permanently (without them restarting), you can use Disable Service to do it for you. You can also use this app to disable certain services from, for example, Facebook, if you don't use them, and save RAM. Alternatives that show more service processes/receivers are Autorun Manager (formerly Autorun Killer) and System Tuner.

(ii) V6 SuperCharger:

Original threads by zeppelinrox: http://xdaforums.com/showthread.php?t=991276, http://xdaforums.com/showthread.php?t=1914159

(there may be other steps in future versions)

1. Download the latest SuperCharger_Starter_Kit_RC12.zip (check thread to be sure)

2. Download the latest V6 SuperCharger script,	V6_SuperCharger_for_Android-Update9_RC13-For_Your_Lag_QF.sh.pdf (right click and "save as", remove the .pdf file extension from the filename, it is NOT a pdf!) (check thread to be sure)

3. Download the latest Ultimatic_Jar_Patcher_Tools_RC7_TEST6_ALL_DEX_ALL_OSes_NO_FLASH.zip (this does not work on Android 4.4 (KitKat) yet!) (check thread to be sure)

4. Put the contents of SuperCharger_Starter_Kit_RC12.zip and the script (step 2) on your phone.

5. Run Terminal Emulator, go to the directory where you put the contents (ls to show directories, cd to move to a directory), type su and enter. Type sh Start* (Note the capital S, not s. The asterisk * is so you don't have to write the entire filename).

5.1. The script will ask you if you want to install BusyBox v1.19.4 (wraithdu). If you already have BusyBox, skip this step.

5.2. The script will ask you if you want to install the su binary v3.1 (wraithdu). You already have the su binary, so skip this step unless you get an error during setting up the V6 SuperCharger script.

5.3. The script will ask you to install the sqlite3 binary. It will auto-detect if you already have it. If you do, skip this step.

5.4. The script will ask you to install the zipalign binary. It will auto-detect if you already have it. If you do, skip this step.

6. Type sh V6* (Note the capital V, not v).

6.1. The script will ask you to select a scrolling speed. Select 0 (not on the list).

6.2. The script will ask you to select the kernel "reboot tolerance". I chose (N)one, most people choose (H)ard I think.

6.3. The script will ask you to use "Entropy-ness Enlarger", select no

6.4. The script will ask you to use "System Property Accessory Tweaks", select yes.

6.5. The script will ask you to use "3G TurboCharger", select yes.

6.6. The script will ask you to use "SD Read Speed Tweak", select no.

6.7. Set BulletProof Apps if you want.

6.8. The script will ask you to use Engine Flush-O-Matic, select yes, I chose 4 hours.

6.9. The script will ask you to use "Detailing", select yes, I chose 2 boots.

6.10. The script will ask you to use "Fix Alignment", select no.

6.11. The script will ask you to use "Wheel Alignment", select yes.

6.12. The script will ask you to use "Fix Emissions", select yes.

6.13. The script will ask you to disable the script animation, select yes.

6.14. The script will ask you to apply "SuperMinFree Calculator Settings", select yes (you can later change the values by selecting either "Unledded", "Ledded" or "Super UL" values).

The following steps do not work on Android 4.4 (KitKat) yet:

7. Connect your phone to your computer with the USB cable, NOT as a mass storage device. Have debugging turned on.

7.1. Unzip the contents from step 3 to your COMPUTER, not phone. Run "ultimatic_jar_patcher_adb.bat" on Windows, "ultimatic_jar_patcher_adb.sh" on Linux or Mac.

7.2. The script will ask you to restart ADB as root, select no, it works without it.

7.3. The script will ask you to "SuperCharge services.jar", select yes.

7.4. The script will ask you to select the launcher strength, select "Die-Hard" (or something else if you want).

7.5. The script will ask you to use the "Maximum MultiTasking Mods", select yes.

7.6. After the script is done, type su and reboot.

8. Open Terminal Emulator, type su and run the V6 script again (step 6).

8.1. The script should say "100% SuperCharged": If it's not, sucks to be you.

Note from the script:

Also recommended is to install the 3G TurboCharger script (right click, save as, remove .pdf extension). Read the generated .html file in the SDcard after running the script to select your preferred values (I chose 4).

(iii) Fly-On Mod™:

Original thread by slaid480: http://xdaforums.com/showthread.php?t=2226373

Download the latest version of the zip - at the time of writing this, it is Signed_Fly-On_Mod™_V4.0-Beta6.zip.

You will have to edit the zip, because there are things that conflict with V6 SuperCharger and CrossBreeder (basically delete all scripts except 98fly_engine and 92cleaner).

Remove the following files:

/system/bin/entropy_on (don't need this)
/system/bin/entropy_off (don't need this)
/system/bin/Fly-On (don't need this)
/system/bin/uninstaller (don't need this)
/system/etc/rngd [B](conflicts with CrossBreeder)[/B]
/system/etc/hosts
/system/etc/init.d/03kill_media_server (you can keep this script if you want, but you don't need it on KitKat)
/system/etc/init.d/sqlite_optimize [B](conflicts with V6)[/B]
/system/etc/init.d/09sdcardspeedfix [B](conflicts with CrossBreeder)[/B]
/system/etc/init.d/darky_zipalign [B](conflicts with V6)[/B]
/system/etc/init.d/zipaligndata [B](conflicts with V6)[/B]
/system/etc/init.d/ram_manager [B](conflicts with V6)[/B]
/system/etc/init.d/94Governor_tweaks [B](conflicts with CrossBreeder)[/B]
(and all the .log files in /data/Fly-On/ that you don't use if you want)

And here is a temporary fix for 92cleaner. Do that.

Save zip (don't flash yet). If your ROM's filesystem is EXT4 (type mount into Terminal Emulator and it should list /system, etc. and say which filesystem it is. If you don't see ext4 anywhere, skip this step), also download the Fly-On_EXT4_tweak.zip. Put both zips on your SDcard (don't flash yet).

Note: if you want, you can leave the files that are conflicting with V6 (except ram_manager!), but then you must disable them in V6 so they don't conflict with Fly-On!

(iv) CrossBreeder:

Original thread by idcrisis: http://xdaforums.com/showthread.php?t=2113150

Download the older 7.2.13 version (needs some manual tweaking for Android 4.3 and 4.4). Goodbye_p_edition and 12.1.2013 are unfinished "work in progress"/test versions and have some bugs. There will be a new app version soon.

Put the zip on your SDcard, reboot into recovery and flash:

1. Fly-On Mod

2. EXT4 tweak (if your ROM supports it)

3. CrossBreeder

Reboot, start Terminal Emulator, run:

su -c "/system/etc/CrossBreeder/ENABLE_GOVERNOR_TWEAKS"
su -c "/system/etc/CrossBreeder/ENABLE_IO_TWEAKS"

NOTE 1: Use CrossBreeder instead of AdAway or AdFree for adblocking. Having a huge hosts file (AdAway/AdFree) actually slows down the network speed! By using CrossBreeder's adblocking engine instead, the network speed is even faster and there are no ads! The only cost is 3 MB of RAM, but it's absolutely worth it. You can still use AdAway to update CrossBreeder's adblock master list. If you have AdFree, uninstall it.

NOTE 2: If you have Seeder (app) or any other entropy generating script, disable them. CrossBreeder's haveged engine is far superior to any other entropy engine. You can use Seeder to check the entropy levels only, but do not enable it. If for some reason entropy does not hover in the 4096 range, force-enable CrossBreeder with (although it should auto-start 99% of the time - maybe it takes a few minutes to stabilize):

su -c "/system/etc/CrossBreeder/zzCrossBreeder FORCE"

(v) Fast GPS lock:

Original thread by sgspluss: http://xdaforums.com/showthread.php?t=2523667

***

Thought I'd also throw this in... Some of my must have apps and other useful apps:

http://xdaforums.com/showpost.php?p=41031365&postcount=15

+

Lockscreen Policy - disable widgets in lockscreen on Android 4.2+

Smart Lockscreen protector - disable reboot/power off/aeroplane mode in lockscreen

Volume Locker - lock volume settings so you don't accidentally mute/unmute with the volume keys in lockscreen

FolderMount - like Directory Bind, but better (supports emulated storage and doesn't run in background)

Disable Service - disable certain processes/services

Autorun Manager (formerly Autorun Killer)

System Tuner

(The above two are similar to Disable Service, but they list more processes and have more features. Also, some processes/receivers detected by Autorun Manager aren't detected by System Tuner, and some detected by System Tuner aren't detected by Autorun Manager. So stupid... Make one app that detects all!)

CatLog

CPU Spy - monitor CPU states

DroidCamX

AnTuTu Benchmark

MX Player + codec

Documents To Go or Quickoffice Pro v5.7.327 (before Google acquired it)

Sygic GPS

Opera Mini (fastest/lightest browser) or Opera

ezPDF Reader - pdf annotation

Seeder - to monitor entropy only, otherwise disabled

Titanium Backup

BusyBox Free

Avast Mobile Security - for Firewall and Anti-Theft only (separate apps). Disable all other features, as there are no viruses for Android, so you're just wasting RAM.

No-frills CPU Control - best setup is:

smartassV2 (governor) + sio (scheduler)

or

SmartassH3 + sio (a little more battery friendly, very tiny (negative) difference in performance from smartassV2)

If smartassV2/SmartassH3 is not available, use ondemand. If sio scheduler is not available, use noop. Also, some people prefer deadline over noop (if available), but most choose noop if sio is not available.