Try CPUspy on the market, will show you what is eating up cpu time.
Heard only good things about Juice Defender.
Don't be using super bright themes (every little bit counts)
Does your kernel support under-volting, you can save a little bit there.
Try different browsers, I still like the default, but found some browsers really heated the phone up.
Also check that your phone is going into deep sleep when the screen is off and not something running that is keeping it awake.
Also don't have programs running that you really don't need
Screens are from Cognition 1.30, but I'm using Cognition 1.42 now and only installed it yesterday, so not sure if its as good with the battery yet, but seems OK.
Edited by quakermaas - 8/17/11 at 1:37am