Top 15 Ways to Extend Your Laptop’s Battery Life

Friedbeef’s Tech has a list of ways to maximize battery life. The tips are general in nature and some don't even apply but generally you can use you most of them. Some of these are -

Dim your screen
Set to the lowest level you can tolerate to squeeze out some extra battery juice.

Cut down on programs running in the background.
All these add to the CPU load and cut down battery life. Shut down everything that isn’t crucial when you’re on battery.

Cut down external devices
USB devices (including your mouse) & WiFi drain down your laptop battery. Remove or shut them down when not in use.

Add more RAM
This will allow you to process more with memory your Eee PC has, rather than relying on virtual memory. Virtual memory results in hard drive use, and is much less power efficient. Note that adding more RAM will consume more energy, so this is most applicable if you do need to run memory intensive programs.

Keep the battery contacts clean.
Clean your battery’s metal contacts every couple of months with a cloth moistened with rubbing alcohol. This keeps the transfer of power from your battery more efficient.

Take care of your battery
Do not leave a charged battery dormant for long periods of time. Once charged, you should at least use the battery at least once every two to three weeks. Also, do not let a Li-On battery completely discharge.

Complete list can be read here.