here are some suggestions:
1: in stock rom when wifi is on and connected to a router, and u went away from in wifi area, it will stop searching for wifi.When u will enter in same wifi zone again, u wont get auto connected to wifi.
Whereas in cm7, after leaving wifi area with wifi on(and connected), upon returning to wifi area again, u will find venue connected to that wifi network automatically.
This means wifi is continuously looking for connection in cm7 but not in stock rom.Make appropriate changes to try and enhance battery life.
I am on 2G EDGE mate
Use this application to save battery.I used it today and felt the difference.
3:Set brightness levels to zero rather than auto.
We have to change our habits of using phones to save battery.Thats a hard fact!