If you'd like to get a preview of your route, tap your destination on the map and choose Directions to Here. Then, instead of using the Current Location option for your starting point, enter your address manually and tap Route. Once you've chosen your route and tapped Start, you'll be able to swipe through the instructions at the top and see exactly which turns Maps wants you to take. (It's the same way you got directions back in iOS 5.)
Location-based reminders for specific locations. If you want to be reminded to do something when you leave your home, work, current location, or any address in your address book, that's pretty easy to get with iOS's Reminders app. But what if you want to remember to buy something when you're at the grocery store or pharmacy? You probably don't want to add their locations in your address book just to get that feature.
Fortunately, you don't have to. When you create a reminder, tap on it and turn on Remind Me At a Location. By default, Reminders will populate your current address--tap that and you'll get a host of options, including, at the bottom, a text box to enter a custom address.
Download a single track from iTunes Match. As of iOS 6.1, Apple has once again restored the ability for iTunes Match users to download any individual track from the cloud onto your iOS device--just tap the cloud download icon next to the entry. In addition, if you decide you want to free up space on your device, you can delete a downloaded track by swiping your finger across it and tapping Delete.
Easier music controls over USB. Perhaps you've abandoned the notion of hooking your iPhone up in your car over USB, because you're so sick of the Accessory Connected screen that dominates the Music app in that setup. Good news! iOS 6.1 improved matters, and--finally--the Music app now remains accessible even when you've plugged your iPhone into a USB playthrough device that lacks the Made for iPhone distinction. It's a delight.