A very underused, yet convenient feature is that you’re able to set the function for double-clicking the Home button.
As with taking screenshots, the image will get stored in the “Saved Photos” library of the Photos app. This one’s actually somewhat intuitive but I was surprised by how many people aren’t aware of it.
Along somewhat similar lines, a handy way of saving a tap when you need to type a capital letter is to touch the Shift key then slide over to the desired key. Do you need to type an umlauted-u (ü) but you’re not using the German keyboard?
You’ll hear a camera shutter sound, your screen will flash white, then the screenshot will appear in the “Saved Photos” library of the Photos app.
Touching an image in Safari or Mail for a couple of seconds will present you with an action sheet which will enable you to save the image.
And finally, if your phone seems to be completely frozen where attempting to turn it off or force quit the current app does nothing, you can force a reset of your phone by pressing both the Sleep/Wake and Home buttons for at least ten seconds.