Do you have any applications running in the background, applications that are constantly accessing data can eat your battery life, such as BBToday, BBWeather ( i set mine to update very very infrequently, if i need it immediately then i ask it to update on the spot). Having the bluetooth radio on all the time also eat up battery life. If you are on a fringe area with your phone and you are switching from EVDO to 1X to 1x also eat up your battery.
BB Tour 9650
Running OS 188.8.131.524