This phone is a CDMA version. As such, it will increase the power output to make a cellular connection. So if you are using the phone where there is no cell or a weak cell, then the phone will go through a battery quickly.
About the only thing you can do is put the phone in airplane mode if you have access to a phone at work and do some housekeeping. You will have to remember to take the phone out of airplane mode when you leave work.
Turning the phone off and back on once a month.
Clearing the system cache once a month. Clearing the Cache
Doing a factory reset when things get really bad.