There are many different ways to extend battery life for your iOS device - this list is some of the key ways you can help get more life from each charge. If you iOS device is not making it through the day - the following tips should help you get more time out of each charge.
1. Turn down the brightness of the display.
Settings --> Brightness
Then turn off Auto-Brightness - which is really Auto make brighter. Then adjust the brightness to the lowest setting you feel comfortable with.
2. Turn off Blue-Tooth.
Settings --> General --> Bluetooth
Then turn off Bluetooth. Going with your wired headphones will save you battery life during the day. Plus getting rid of that bluetooth earpiece will keep you from looking like Lando's PA.
3. Turn on Autolock
Settings --> General --> Autolock
Then set it for 1 or 2 minutes. Yes it is might seem like a pain to have to unlock your phone each time you need it - but at least it will still have juice left to use.
4. Turn off Location Services
Settings --> Location Services
If you can turn off all location services. If however like most people you do need location services for apps like the Maps app - then manually select which apps you want to allow to use location services. You will be surprised by how many apps you have that use location services and the more you can turn off the better.
5. Close out all apps running / parked in the background.
Double Tap the home button. Then hold down on one of the apps that are in the App tray. Then go to town clicking on all the red X's. Apps like Skype that are parked in the background can still chew up lots of juice from your battery.
6. Turn off Wifi
Settings --> Wifi
If you are going to be out and about and don't plan to be using Wifi - turn it off. Even if you think you will be using it - turn it off now and then back on when you are in range of your trusted Wifi connection.
7. Turn off Notifications
Settings --> Notifications
Ok - other than the Tii App do you really need Notifications? Ok maybe for a couple of other apps. Same as with Location Services - find the Apps you really want to get Notifications for and turn off the rest of them.
8. Push e-mail
Settings --> Mail, Contacts, Calendars --> Fetch New Data
If you have Push e-mail set up for any email accounts you can change it to only check for new emails when you actually have the email program open.
9. Use the Jailbreak App - Auto3G
This app works by switching to Edge mode and turning off your 3G radio when you lock your phone and then switching back to 3G when you unlock. Not saying this is something Apple should have built in on their own - but.... Maybe it will be in iOS 5.
10. Turn off 3G (gasp!!!)
Settings --> General --> Network --> Enable 3G
Turn off 3G - Yikes!!! - Ok - this is a drastic step - But if you don't jailbreak then item 9 above is something you can't do and if you need the phone to be just a phone for most of the day, to occasionally check email and to listen to your favorite podcast. Then turning off 3G will actually save you quite a bit of juice.
Granted doing everything above pretty much dumbs down your smartphone and you would in many cases be better off getting a battery case like one from Mophie. But even doing just a few items above can help extend your battery life more than enough to get through a full day.
If you know of any battery saving tips not included - please include them in the comments below.
