Are you in tune to your customers?
Apps need to be proactive in encouraging customers to speak out. Hav- ing an easy to find "Feedback" or "Contact Us" button inside the app is important to encourage communication.
Cover all your bases by listening to your customers via social networks and setting up Google Alerts to hear about any mentions of your app on the web. You should have analytics in place to see how often customers are using your app, what features they use, and what features they ignore.
Answering these questions will give you the insight to improve on the aspects that bring your customers back and change the parts that drive your customers away.