I have come across a great article on Getting Started with App Previews, in iOS 8, that I thought I might share. With the introduction of App Previews, how your app is visible on the App Store becomes even more prominent, and it's crucial you take advantage of adding an app video, which essentially is your 20-second pitch as to why your app should be downloaded.
Engage customers with a short video of your app in action, directly on your app product page on the App Store. By showing the experience of using your app, App Previews can help customers better understand your app and encourage more downloads. - Apple
Dan Counsell makes some great points on how to encapsulate the essence and spirit of your app in a presentational format, appealing to the masses, from start-to-finish. So make your way to his article, by clicking here.