Source: http://support.t-mobile.com/docs/DOC-2548

I recently got a new HTC One S phone, and along with it came an issue of high battery usage. Luckily, a new firmware is out to help with this, but below are general guidelines to help you manage your battery life.

Possible causes of high battery usage:

• Services such as Wi-Fi or GPS are running
• Backlight or notification settings
• Third party applications running in the background
• Data synchronization settings

To conserve battery power and prolong battery life (some features referenced here may not be available for all device models):

• Turn off Wi-Fi when not in use
• Turn off Wi-Fi Calling when not in use (if available on your phone)
• When Wi-Fi is on, turn off Best Wi-Fi performance:
  • From the Home screen, press the Menu key
  • Touch Settings
  • Touch Wireless & networks
  • Touch Wi-Fi settings
  • Press the Menu key
  • Touch Advanced
  • Verify the Best Wi-Fi performance check box is cleared (turned off). If you have connectivity issues when it is turned off, you may turn it on to stay better connected, but it will consume more battery.

•  Turn off Bluetooth when not in use
• Turn off GPS when not in use
• Increase the data synchronization interval
• Decrease screen brightness
• Shorten the backlight timeout duration
• Turn off vibration
• Turn off notification sounds
• Use the Power Saver to set power saver options (check documentation for your specific model to see if Power saver is available on your phone)
• Plug the phone into its charger when it is not being used
• Turn off Fastboot. Fastboot allows your phone to turn on quickly by hibernating instead of turning off completely. Turning off Fast boot will use less power, but the phone will take longer to turn on.
  • From the Home screen, press the Menu key
  • Touch Settings
  • Scroll to and tap Power
  • Touch the Fastboot check box to clear (turn off)