What are some ways to improve iOS 5 device battery life, for iPhones and iPads?

"Disable "push" email and switch to manually fetching only." This one is a bit of a myth, as it depends largely on your specific situation.  While moving to completely manual fetching will definitely help, most users mistake this for meaning using "fetch" instead of "push" and then gleefully set their fetch interval to 15 minutes.  The problem with this is that in most cases this uses significantly more battery life than push, particularly in the case of MobileMe/iCloud push. The iPhone Mail process consumes the most battery when actually connecting to the network to check for new mail.  When MobileMe/iCloud push is enabled, the iPhone sits completely idle unless it specifically receives a network push notification that new mail is pending, at which point it goes out and polls for mail the same way that it would if you were fetching manually. The reasoning is that most users do not receive mail so frequently that using push-based mail would actually cause the iPhone to go out and fetch mail more often than the normal 15 minute schedule, meaning the Mail app should consume less battery life with push enabled than it would to be fetching mail every 15 minutes regardless of whether there was new mail or not. Now obviously there's a tradeoff here and longer fetch schedules will be better, and actual manual fetching is the best option of all in this regard.  Note that Exchange ActiveSync Push is a little bit different than MobileMe/iCloud push in terms of the protocols used and the power consumed, so the tradeoff here between battery life and mail fetching is going to be different, but again it's going to depend on how much mail you normally receive via push versus how often you would otherwise be fetching, since even the persistent HTTP connection used by ActiveSync requires (marginally) less power than an actual IMAP connection since virtually no data is being transferred beyond a "keep-alive" request at regular intervals. Note that regardless of all of the above, battery life consumed by any mail process is pretty much at the bottom of the list compared to things like Bluetooth, Wi-Fi, screen brightness and location services.  Another setting that will dramatically improve battery life is toggling off 3G data. This will limit you to slower EDGE network speeds (assuming your carrier supports them), but if you're concerned about battery life you're probably not doing much web browsing anyway :)  Note that some carriers, such as Bell and Telus in Canada, only have 3G networks, so turning off 3G in these cases will effectively disable all data access.

Here are a few tips: 1. Turn Off Keyboard Clicks Sound 2. Disable Background App Refresh 3. Turn off the Parallax Effect/Animations 4. Turn off Wifi/Bluetooth/Airdrop 5. Disable Location Services 6. Close Running Apps in the Background 7. Remove the App Garbage Files by CleanMyPhone Source: http://www.fireebok.com/resource/how-to-improve-battery-life-on-your-iphone.html