1)Google Adwords: This is a great way of app promotion.
Google promotes the app in the google search, you tube, play store. If anyone search related to an app in google
play store then the apps ads show in first results. this gives maximum downloads. But This way more costly than another promotion ways. To promote the app with Google Adwords
you have to create a universal app campaign. It provides you
the option of select language, country, regions to target the customer.
2)Youtube: This way gives you to largest app downloads at a cheap cost. You
have to contact only the App related youtube channels
for the promotion of app through emails. The youtube promote your app in video and also give a link of app download in description.
3)App Store:To get more Downloads also upload app in amazon app store,9Apps,mobogenie,apptoide,Getjar etc.
4)Blog or website: To promote the app make a blog or website which Gives information of app.
5)Referral system in app: Provide the referral system in app which gives some reward after sharing app in social media like WhatsApp,Facebook,Instagram etc.