Manage expectations. Your app description must clarify what it does and doesn't do. It should be short, bullet pointed and not full of jargon.
Managing expectations when producing an app is vital. Not doing so leaves users disappointed and could potentially damage your brand.
Take the Sainsbury's app for example. Do you expect to be able to buy your food shopping on this app? Most people would answer 'yes' to this question. So the question is, if you can't order shopping on this app, what's it for? It can find your nearest Sainsbury's, tell you about the latest offers and provide you with Sainsbury's news. Whilst these features are nice to have, it is questionable whether this is what users expect. User reviews include Sainsbury's need to launch an iPhone shopping app, I for one have defected to Tesco's. Come on Sainsbury's, keep up with Tesco. This app is useless. We want a Sainsbury's shopping app, not a guided tour to nowhere!. In their defence, however, the app description does outline what it does in reality: a store locator, information about top deals, Sainsbur's news and Nectar points information. Despite this though, this app fails to meet users' expectations.