As most of you know, you can tell when the phone is not getting what I consider reasonable battery life.
Here are the things that I found worth doing:
1: Greenify apps if you can. Unfortunately, Facebook is one of the worst violators of battery and if you greenify it, you will go a long way towards having decent battery life. Of course, then you don't get your Facebook notifications, but for me, this is a plus.
2: Battery Doctor. You can set it to kill apps when the screen is off. There is a whitelist as well so you can keep certain apps running instead being killed.
3: Adjust the auto brightness curve. This seems to work well. Keep the screen reasonably bright but no more than necessary. I think this might work better than just a fixed brightness level because if the area gets really bright, at least the screen will react and become brighter so you can still see the screen. To me, the screen is a battery killer.
4: If you have a super AMOLED display supposedly you can black out the screen with a dark UI. Not sure how much this helps.
5: Custom Kernel. I have only tried IceCode and insanity. Both were giving reasonable battery life. I tried the lower voltage tables in IceCode but didn't notice much difference.
For me, even though I tried several different ROMs, if I did the above, I got reasonable standby/sleep times. It was usually 1 to 1.5 percent per hour in sleep. When the screen was on, battery life was totally dependent on screen brightness. For me, reasonable is with decent use - check/reply to mail a few times an hour, browse web, text, talk abut an hour a day, etc... from 7a-3p and still have around 70% left. For me, the phone still needs charging every day though. Any other tips???