There is no fixed formula many similar games are available on Google Play Store but not all are popular. Similarly out of various messaging application not all are heavily downloaded.
Either build a game with superb graphics and addictive game play or build a utility app or just think out of the box to provide something extraordinary service. Once your download reached 100,000 subscribers, you would be able to make decent money out of it. If your application is useful enough that people are ready to pay for it, you could earn even more.