If you're on the ICS leaks or anything higher make a custom rule for battery extender in Smart Actions. You don't even need to install an app from the Play Store, and it works better than JD in my experience. JD would bug up my data connection a lot, but it happens with the Smart Actions like once every other day. Seeing as it's turning on and off every time my screen turns on and off and I use my phone all day it's pretty successful. Get Battery Widget Reborn to keep up to date on your battery info. My battery averages 18 hours and 50 minutes to die. I don't sacrifice my 4G, my GPS is on, and it's overclocked to 1.2 Ghz. I have the extended battery though so that may be part of it.