We all use our phone for different things from making phone calls, texting, taking pictures and videos. Here are some tips when you find yourself with a low battery and need to conserve power.
This should work with any S60 phone and features may very.
turn off email retrievals
close any unnecessary applications running in the background
set your screen brightness all the way down, as well has your light time-out
don't use any gps
turn off wlan searching
don't text or call unless its absolutely necessary
turn off the "show captured image", or image preview in your camera settings
in drastic times, set your phone to offline mode under the profiles.
turn off the automatic screen rotation
lower the power saver timeout settings.