When you're wearing EarPods or another set of headphones with built-in remote controls, pausing and playing music is as convenient as it gets. However, some of the better sounding headphones out there do not have remotes built in, so pausing a song when you need to is at least a few steps, which is a few steps more than I want.
There is a way to pause a song immediately without looking, and all it takes is for you to remove your headphones from the jack on your iPad, iPhone, or iPod touch. This is especially helpful when driving, if you're connected via an audio input cable to your stereo, since you don't have to remove your eyes from the road.
If you don't like pulling the plug, there's another eyes-free way to pause a song you're playing, but you'll need to be using a jailbroken iOS 7 device. If you already updated to iOS 7.1, this tweak isn't possible for you, since the last Apple update breaks the last working jailbreak.
This tweak lets you pause a song or video just by using the volume rockers on the side of your device. Just press and hold the Volume Down key to lower the volume. One it reaches zero, it'll automatically pause. This works with the screen on and off. To play it again, press and hold the Volume Up key and hit the level you want. Playing only works with the screen on, though.
Install and then respring your device to ensure the changes will take place upon reboot. Once you reboot the device, the tweak will already be applied—there are no other settings to mess with.
Now, when you play music from the stock Music app, Pandora, Spotify, or whatever, playback will automatically pause whenever you bring the volume down using the rockers on the side of your iPhone.
But wait... there's more. AutoPause also works for videos in browser. If you are watching a YouTube video in Safari or Chrome, AutoPause will pause the video when you bring the volume down to zero.
This currently does not work inside video applications like YouTube or Netflix, but future updates may bring that functionality.
Needless to say, this is a super convenient and very simple tweak to add to your phone, if you tend to pause movies or tunes all the time. Maybe one day the dev will be able to get the Volume Up key to work when the screen off, but until then, it's still pretty legit.