If you don't use CPU intensive apps or games then go to Power Saving and check CPU Power Saving.
HUGE improvement in battery life for me. I was down to about 20%+ after 8 hours at work with mostly using tweetcaster, AC forum app, texting, and light Internet use. I had to charge the phone around noon to get me through the rest of the day.
Today, I'm at 50%. Screen on time of 2hr 35mins.
And there is NO lag, slowing down, or any other visible issue from turning the power Saving on.
Sent from my SCH-I535 using Android Central Forums