Google Nexus One is pretty decent phone, but the major issue with the users of nexus one is the low battery backup. In order to save the battery you need to turn off of the features and functions whenever you are not using them.
Follow the following tips to increase the battery back in nexus one and other android phones.
1. Turn Off Bluetooth
2. Turn Off GPS
3. Turn Off Wi-Fi
4. Turn Off Sync
5. Decrease Excessive Of Brightness Level – Use Low Battery
[ All above can be done through the power widget ]
6. In order to turn off auto syncing to gmail, contacts and calendar to save more battery
7. You can also turn off animation features which will also save the battery to some extent
7.1 Go to Settings >> Display – Brightness as shown in the image below
8. You can also go to Settings >> About Phone >> Battery Use as shown in the image below.