Tip 5: Buy a mobile charger or battery-equipped case, like the Mophie.
The aforementioned software adjustments will help, but they will only go so far, at least after a day of heavy use. If that extra juice doesn't go far enough, take the plunge: buy a mobile charger or case on hand.
There are a number of mobile chargers with Micro USB or Apple's charging connectors. I particularly like the $50 PowerStick and Mophie's JuicePack Power Station. If you have an iPhone or a Galaxy S3, though, the best solution is the Mophie case. The phone case has another battery inside it. It makes the phone pretty chunky, but it also doubles your battery life. It's all about compromise.
The new Mophie Juice Pack Air for the iPhone costs $100 and the version with the smaller battery, called the Helium costs $79.95. Both of the cases can be turned on and will charge up your iPhone when it's almost dead.
When my iPhone 5 had 5 percent of a charge left, I got a full charge with the Air and about 80 percent of a charge with the Helium. Still, having either option will eliminate the anxiety you have about losing power throughout the day and that dance of looking around for a power outlet.