1. Dont use task killers...it doesnt work with Froyo and it doesnt help...uninstall it.
2. Empty the battery to the 0% and leave it on charge when phone is off all night.
3. Turn it ON and use it untill it die again...then again turn it off and charge it for 3 hourse. Turn it on...its calibrated
4. Use 2G if you dont need 3G
5. Use max 70% of display light
6. Use only must have online update programs
Thats all...I did that on HD2 and I didnt have any problems for all day...and I used it normaly. In stand by it was 1,5% per hour... with mp3 was 10% in 1hour...etc...
HTC HD2 (LEO)
1.66 WWE EastEurope