If you want to know what percentage of the battery is being drained and how quickly, get
My Battery Drain Analyzer
If you want to know what's running, get
Better Battery Stats
The original posting with a lot of information about Better Battery Stats is
HERE
Even further detailed information and about how to interpret the program is
HERE
If you only use your WiFi or GPS at certain times throughout the day, then you may want an app that is good at setting profiles for your phone based on time. I wake up, go to work, come home and go to sleep at the same time every day... so this app is great for me -
PhoneWeaver.
The above is a trial, if you like it, buy the full... it's VERY worth it.
DON'T kill apps with "Startup Manager" and "AutoKill" programs... they do more harm than good...
HERE'S WHY. Use Better Battery Stats and review the Wakelocks and see what is running and not letting your phone chill(no pun intended). The Battery Drain Analyzer will tell you how much is being drained in percentage format... use this before and after every time you make changes that could affect the battery to see how much improvement or harm you've done.
I use all of the above, and recommend it all highly. Let me know if you have questions on how to use them. Also, if you don't use your GPS, leave it off - big battery hog. And remember... keep your brightness AS LOW AS YOU CAN COMFORTABLY HAVE IT!!! (Also a setting in PhoneWeaver)