Check if you have any open services (apps) running and try to close them. Also have you rooted your phone? If so try to remove the LG bloatware, because this will also eat your battery. What you also could do is to match your baseband with a matching RIL with the GetRIL app. This will improve signal and battery life.
Also, look in this thread for more tips:
Last edited by SP1996AC; 4th February 2012 at 08:58 PM.