First thing I would do is calibrate your battery
meter to ensure your readings are correct. The following advice comes from Professor FoxKat, our resident battery wizard.
1. Power OFF your phone and let it charge to 100%. You can check the level of charge by pressing either volume button.
2. Turn your phone back on and use normally until you get the 'low battery warning' at 15%.
3. Repeat step 1.
4. Repeat this process every other month or so.
Once that's done, try enabling some Smart Actions like Battery Extender, which will allow you to turn off cell data, background sync, etc, (whatever you choose) while your display is off. You can also try using Task Manager, which will auto-end apps you select two minutes after the display is off. Note: some of this info might change once ICS is released to the masses, but the gist of it remains the same.
Finally, take a look at the Battery Forum -
Smartphone Battery Discussion. Lots of good tips there too.