Hi there, based on your situation, here are some effective ways for you to drtive more downloads.
App Store Optimization
App store optimization (ASO) is, at it’s core, search engine optimization (SEO) for App stores. Just like search engine optimization, app store optimization focuses on keyword relevance, search relevance and the keyword density in your description, which aims to boost your app ranking in app stores. You metioned that your app is with many positive reviews and high ratings, then once your app ranking is improved,you will get much more downloads. So ASO is the most efficient way to promote app, if you know little about it, you can consult app store optimization company,which can provide you professional app store optimization advice.
Run Facebook Ads
App Install adverts enable businesses to connect with the people who are more likely to install your app, so you can get more people using your app. Mobile App Install adverts link directly to the App Store, Google Play and Kindle Fire store, so that people can download your mobile app straight away. And they can be shown across Facebook, Instagram and Audience Network.What’s more, through Paid Installs you can customize each ad and target specific groups of customers and users. Facebook Ads give you the opportunity to adjust your budget, so could be a great way to get the ball rolling and test CTA’s, app descriptions and headlines.
Most people like to follow others and be influenced by the words of influencers. These people may include influential bloggers, newspaper journalists, professional tech writers in social network like Facebook or Twitter.
CPI Burst Campaigns
Most of the traffic from searches on both Google Play and the App Store will go only as far as the 50th app in the list. Naturally, developers strive to make their app reach the highest position. One method is by making use of a CPI (Cost-Per-Install) Campaign via different advertisers. The idea is to propel yourself in the list of Top 50 apps in your niche. If you reach that spot, the effects will last long enough for you to get your money’s worth.
Free a day/Offer discounts
If your app is paid, or you are are working with in-app purchases, offer them at cheaper prices on certain days or free a day, and let your users know via push notifications or your email newsletter
Hope these methods are useful to u.