1. You must think about new ideas related to your app, before build any app. you do market research for much better ideas of how to position and market your app.
2. Build a right app and build it right.
3. Choose the right name of your app, always choose app name which is relatively, explicit and contain a good keyword.
4. Develop a great design for your app.
5. Do inboud marketing & real life marketing.
6. Social networking sites are the best way to promote your app.
7. Promo video is also a good way to promote your upcoming game. It show that what your app is all about.
8. Feedback & reviews.
9. Engaging people and generating interest.
10. Website & blogs.