Realmac Software has a nice post on their blog, outlining a few tips on how to keep your iOS device secure. The one I didn't know about involves the passcode lock:
Before you Turn Passcode On you should consider whether to turn Simple Passcode off. With Simple Passcode on you will set a 4-digit number, with it off you can set a longer alphanumeric passcode. Longer alphanumeric passcodes are more secure but also a little more fiddly to enter on the lock screen as you'll be presented with the full keyboard instead of the numeric keypad. But here's a pro tip where you can get best of both worlds. If you have Simple Passcode off and set a long passcode that only contains numbers the lock screen will now present the numeric keypad instead of the full keyboard. Now you can choose a longer, more secure numeric passcode which is both easier to remember and quicker to enter that an alphanumeric one.
Pretty nifty if you ask me. Head over to the post on the Realmac Software blog for the other tips.