a)Keep the wireless LAN when not required.
b)Charge the laptop battery only when completely drained.
c)Please keep the laptop on the minimal power management option from the following path:Start->Control panel->Power options->minimal battery battery mode.
d)Defragement your hard drive regularly.
e)If you have a graphics card but rarely use it then keep them of by using softwares like powermizers and powerplay.
f)Reduce backlight.