There are a couple of things you can do to try and improve the life of your battery.
Start with calibrating your battery so you are getting the most accurate reading. To do this, search for "battery calibration" in the Market/Play Store. Choose the first result and download it. When the installation is finished, press the "N" button.
Open the App Drawer (the four-square icon on your home screen). Tap "Battery Calibration." A Superuser Request window will pop up, after which you will press "Allow."
This alone should help improve your battery life, but there are also some other tips to help as well.
One of the biggest drains on your battery is the display. While it might not be practical to turn this off since you wouldn't be able to see anything, you can still turn the display brightness down. To do this, press the menu button from the home screen.
Choose "Settings," "Display" and finally "Brightness," after which you will see a sliding bar that you are able to adjust. The lower the brightness, the longer the battery life. Once you have chosen a level, click "OK."
Another way to improve your battery life is to turn off animations. To do this, go to the menu from the home screen. Choose "Settings," "Display" and then "Animation."
Select "No animations."
Wi-fi is also a notorious drain on your battery. If you don't need it on, turn it off by going to the menu from your home screen, choose "Settings" and then "Wireless & network settings." From here you can click off the box for "Wi-Fi" to turn wi-fi off.