1. Make Simple Design.
2. Show me just what was needed.
3. Only interrupt, if it matters.
4. Save the short message, use an image.
5. Never Allow eliminating your user data.
6. users to do important things quickly.
There are other common design best practices, which are listed here:
Design for performance – Applications are designed to be started quickly. You should target an average of less than one second to launch the application. All potentially slow operation should be done asynchronously.
Design for optimal battery life – Your app should consume as little energy. Stop updating the user interface and the listener if your application is not currently visible.
Source: Master Android (App)