Pinch with 5 fingers to close the current application.
—Pierce Freeman, iOS Developer

Keyboard shortcuts for commonly-used sentences/phrases, perfect for text notes in SportsBoard Apps.  Once acronyms and their respective meanings have been created, you can quickly plug in the abbreviation and the full sentence will display.  Thus saving time spent staring at the iPad screen typing!
To do this go to Settings—>General—>Keyboard—>Add New Shortcut
—Stephen Kiraly, Inside Sales

Now you don’t need to rely on third party software to type smiley or emoji characters as the iOS 5 and 6 include a built-in Emoji keyboard.
To type a smiley or emoji character, tap the “International” key on the keyboard (or touch and hold the key, then slide to Emoji), a plethora of emoji characters are then at your fingertips.
On my device upgraded to the iOS 6, the Emoji keyboard is enabled by default. In the iOS 5, you can enable it in a few steps:
1. Go to Settings > General > Keyboard
2. Tap “International Keyboards” and “Add New Keyboard…”
3. Select “Emoji”
Apple: “iOS: Understanding emoji”
—Deanne Brock, Inside Sales

Closing apps you have open to improve performance (double-tap home button, hold down any app, and hit the red minuses)
Apple: “iOS: Force an app to close”
—Jack Dagley, Inside Sales

Double-tap the spacebar at the end of your sentences to add a period and a space to start the next sentence.
—Spencer Homich, Inside Sales

Settings > General > Accessibility > Invert Colors
Apple: “iOS: Configuring accessibility features”
—Mitchell Cde Baca