build.prop tweaks in common raw format (edit needed to adapt to device)

build.prop.tweaks

#
# TWEAKS
#

# Qualcomm
#com.qc.hardware=true
#debug.qctwa.statusbar=1
#debug.qctwa.preservebuf=1
#debug.qc.hardware=true

# Disable Bootanimation For Quicker Boot
debug.sf.nobootanimation=1

# Increase speed for UMS transfer
ro.vold.umsdirtyratio=50

# Performance
debug.performance.tuning=1
video.accelerate.hw=1
debug.egl.profiler=1
#debug.egl.hw=1

# Rendering User Interface With GPU
#debug.sf.hw=1

# Faster Streaming
media.stagefright.enable-player=true
media.stagefright.enable-meta=true
media.stagefright.enable-scan=true
media.stagefright.enable-http=true
media.stagefright.enable-record=false

# Better Image & Audio Quality
ro.media.dec.jpeg.memcap=8000000
# ro.media.enc.hprof.vid.bps=8000000
ro.media.enc.jpeg.quality=100

# Net Speed Tweaks
net.tcp.buffersize.default=4096,87380,256960,4096, 16384,256960
net.tcp.buffersize.wifi=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.umts=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.gprs=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.edge=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.hspa=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.lte=524288,1048576,2097152,5242 88,1048576,2097152
net.tcp.buffersize.lte=262144,524288,3145728,262144,524288,3145728
net.tcp.buffersize.hspda=4096,87380,256960,4096,16 384,256960
net.tcp.buffersize.evdo_b=6144,87380,1048576,6144, 87380,1048576
net.tcp.buffersize.hsdpa=6144,262144,1048576,6144,262144,1048576

# Battery Tweaks
pm.sleep_mode=1
ro.ril.disable.power.collapse=0
ro.ril.fast.dormancy.rule=0
ro.ril.power_collapse=1

# Frees More RAM
persist.sys.purgeable_assets=1

# Signal Tweaks
ro.ril.hsxpa=2
ro.ril.gprsclass=10
ro.ril.hsdpa.category=10
ro.ril.hsupa.category=5
persist.cust.tel.eons=1
ro.config.hw_fast_dormancy=1
ro.ril.enable.dtm=1
ro.ril.enable.a53=1
ro.ril.enable.3g.prefix=1
ro.ril.hep=1
ro.ril.htcmaskw1.bitmask=4294967295
ro.ril.htcmaskw1=14449

# Better call voice quality
# ro.ril.enable.amr.wideband=1

# Fast Reboot
persist.sys.shutdown.mode=hibernate
ro.config.hw_quickpoweron=true

# Better Responsiveness & Speed
windowsmgr.max_events_per_sec=90
ro.max.fling_velocity=12000
ro.min.fling_velocity=8000
ro.min_pointer_dur=8

# Fix App Issues
ro.kernel.android.checkjni=0

ro.kernel.checkjni=0
vm.stat_interval=1
persist.android.strictmode=0
profiler.force_disable_err_rpt=1
profiler.force_disable_ulog=1

# Disable sending usage data
ro.config.nocheckin=1

# Enables 270 Degree Rotation
#windowsmgr.support_rotation_270=true

# GOOGLE DNS
#net.dns1=8.8.8.8
#net.dns2=8.8.4.4
#net.rmnet0.dns1=8.8.8.8
#net.rmnet0.dns2=8.8.4.4
#net.ppp0.dns1=8.8.8.8
#net.ppp0.dns2=8.8.4.4
#net.wlan0.dns1=8.8.8.8
#net.wlan0.dns2=8.8.4.4
#net.eth0.dns1=8.8.8.8
#net.eth0.dns2=8.8.4.4
#net.gprs.dns1=8.8.8.8
#net.gprs.dns2=8.8.4.4

# Support For IPV4 and IPV6
persist.telephony.support.ipv6=0
persist.telephony.support.ipv4=1

# Wireless Tweaks
net.ipv4.ip_no_pmtu_disc=0
net.ipv4.route.flush=1
net.ipv4.tcp_ecn=0
net.ipv4.tcp_fack=1
net.ipv4.tcp_mem=187000 187000 187000
net.ipv4.tcp_moderate_rcvbuf=1
net.ipv4.tcp_no_metrics_save=1
net.ipv4.tcp_rfc1337=1
net.ipv4.tcp_rmem=4096 39000 187000
net.ipv4.tcp_sack=1
net.ipv4.tcp_timestamps=1
net.ipv4.tcp_window_scaling=1
net.ipv4.tcp_wmem=4096 39000 18700
wifi.supplicant_scan_interval=180

build.prop edits are very easy and useful, they can be applied on stock rom/kernel, i have compiled this from various sources!
For ICS, most of these will be useless

Locate build.prop
got to system/ and find build.prop

Edit with notepad++. Save and overwrite previous file, then change permissions to rw,r,r!
Change the tweaks already present and add new at the end of file!

Change android name and version
ro.build.display.id=Your ROM name
ro.build.version.release=2.3.6 (Android version number)

Decrease boot time
debug.sf.nobootanimation=1 (Disables bootanimation)
ro.config.hw_quickpoweron=true
persist.sys.shutdown.mode=hibernate
dev.bootcomplete=0

Power saving
ro.ril.power_collapse=1
pm.sleep_mode=1
wifi.supplicant_scan_interval=120 (sets wifi scanning interval, can be increased or decreased)
ro.mot.eri.losalert.delay=1000 (might break tethering)

3G Tweaks
ro.ril.hsxpa=2
ro.ril.gprsclass=10
ro.ril.hsdpa.category=10
ro.ril.hsupa.category=5
ro.ril.enable.a53=1
ro.ril.enable.3g.prefix=1
ro.ril.hep=1
ro.ril.enable.dtm=1
ro.rill.enable.a53=1

Telephony/ring Tweaks
ro.telephony.call_ring.delay=0
ring.delay=0

Proximity (Disable blackscreen issue after call)
mot.proximity.delay=0
ro.lge.proximity.delay=25

Smooth Scrolling
windowsmgr.max_events_per_sec=84(This value is experimental)
ro.max.fling_velocity=12000
ro.min.fling_velocity=8000

Disables error reports
profiler.force_disable_err_rpt=1
profiler.force_disable_ulog=1

Force home launcher into memory(use light launchers only)
ro.HOME_APP_ADJ = 1

Render UI with GPU
debug.sf.hw = 1

Disable logcat
logcat.live=disable

dalvik.vm.heapsize = 64m
Note: This value is different for different phones, the value can larger(128m) with larger RAM device, use accordingly!

Phone will not wake up from hitting volume rocker
ro.config.hwfeature_wakeupkey=0

Change LCD density
ro.sf.lcd_density=160

Allows purging of assets to free up RAM
persist.sys.purgeable_assets=1