Hi there, based on my experience, here are some effective ways for you to increase your app visibility, details as follows:

Cooperating with influencers
Most people like to follow others and be influenced by the words of some celebrities or well-known business people - having high-profile Facebook pages with 100,000+Likes mentioning your app is a huge win. Reach out to organizations whose goals align with yours, and give them a compelling reason to mention or link to your app on their page.Pay for their recommendation is a good choice.

Apply for Awards and Contests
One great way to get exposure for your mobile app is to enter – and win – contests. It can give you tons of press, exposure, reviews, and plenty of downloads.There are tons of organizations that give prizes to new, innovative applications for their functionality, design, and so on.

Get Featured On Mobile App Review Sites
There are many sites you can submit your app, such as cnet,mashable, techrunch, app advice, appbrain,etc. If you get reviewed by a popular app blog like AppAdvice, you can expect a similar amount of traffic to flow through to your website and App Store listing. If you get featured on The Next Web, you can expect tens of thousands of unique visitors in the first 24 hours to hit your website and your app store page.

Before promoting your app, you should also get positive app reviews(Bestreview provides this kind of service, https://www.bestreviewapp.com/?from=cr-chris) to increase the download rates, because 95% users will take the app reviews as one of the most important reference factors to judge the app, and most people prefer to download an app which has much more positive reviews.

Hope these methods are useful to you.