What works for me is to go to Applications>Options>Screen/Keyboard and reduce the Background Brightness down to 10% which, believe it or not, is ample brightness. This seems to extend my battery life by quite a few days
Despite the buzz kill comment below....you asked the question here....my two cents:
I manage my bluetooth....I assigned the lower right hand side convenince key to manage my connections. When I get out of the car I turn off my blue tooth. By doing so I can recharge my phone every other day instead of every day.