Have a good keywords (around 5 times in your app's descr). But the important for me is number of download and good rating.
To increase app ranking of your app you need to promote Content with your potential keywords that customers are using to find apps.
Use the right keywords, strive to increase number of installs, and promote, promote, promote. Promotion could be free, but sometimes, paid ads could be a better option. Good luck!
Hi, It is advisable to create and rank/promote a web page with fresh and unique information(content) about your Android app on various search engine and does promote as well on various high DA and most relevant website to create online popularity of your android app. If once your app is getting online popularity then the number of installations is increased. If the number of installations is increased then your app is getting better ranking on Google Play Store as well. Note - Don't forget to use fresh content and set proper keyword density in the app description on Google Play Store.