heres my tips for extending battery life.
1. Get a screen brightness widget there is one on the HTC power widget that comes with the phone. Theres also a few on android market for free. The default screen brightness eats the battery. With the widget you can keep it on the lowest setting which is fine for indoor use, if your outside use the widget to turn it up. This is the biggest battery saving method i have found.
2. Theres an app called "juice defender" you get a free version and a paid version which has more options. I ended up buying "ultimate juice" for the extra features. Its ok but screen brightness i think makes a bigger diffirence.
3. Make sure in your options you have the screen to turn off automatically after 1 minute. Again this is becuase the screen power eats battery you dont want it on when your not using it.
hope that helps.
