Want to save battery life on your iPad 2 or iPhone 4? Switch up the data push frequency.
The process of data exchange is a drain on battery life. So Apple has given users a great deal of control over how often the iPad 2/iPhone 4 fetch new data. In Settings -> Mail, Contacts, Calendars -> Fetch New Data, try setting Fetch to Every 30 Minutes or even Hourly if possible.
You can get even more granular: for email or calendar accounts that are used infrequently, go to Settings -> Mail, Contacts, Calendars -> Fetch New Data -> Advanced. You can then set each one to Manual rather than Fetch. Once set to Manual, email accounts will only push new emails when the Mail app is opened and calendar accounts will only sync when the Calendar app is opened.
See Tip and Trick #30: Type in Multiple Languages
See Tip and Trick #29: Character Count Your Text Messages
See Tip and Trick #28: Accessing the Scientific Calculator
See Tip and Trick #27: Zooming on Google Maps
See Tip and Trick #26: Accessing “iPod” While Device is Locked
See Tip and Trick #25: Adding Accents While Typing
See Tip and Trick #24: Search Web/Wikipedia from Home Screen
See Tip and Trick #23: Quick Call Handling
See Tip and Trick #22: Email Web Pages
See Tip and Trick #21: Enabling “Caps Lock”
See Tip and Trick #20: Take Images Straight off Safari
See Tip and Trick #19: Setting the “Home Button” Double-Tap
See Tip and Trick #18: Invert Display Colors
See Tip and Trick #17: Turning Web Pages into Icons
See Tip and Trick #16: Refined Spotlight Search
See Tip and Trick #15: Ditch typing URL Extensions in Safari
See Tip and Trick #14: How to Sync Your Boomarks Using iTunes
See Tip and Trick #13: How to Use Enhanced Camera Functionalities
See Tip and Trick #12: Shut Down Running or Suspended Apps
See Tip and Trick #11: How to Create Folders
See Tip and Trick #10: How to Edit and Create Documents
See Tip and Trick #9: Set the Device to Self Destruct
See Tip and Trick #8: Choose an App for Opening an Attachment
See Tip and Trick #7: Orientation Lock the Screen
See Tip and Trick #6: Forget a Wifi Network
See Tip and Trick #5: Change Your Email Signature
See Tip and Trick #4: Take a Screen Shot
See Tip and Trick #3: Download the PDF User’s Guide
See Tip and Trick #2: Check a URL Destination Before Opening It