How to promote Apps outside App Store?

[avinash]

You can suggest her anything you want!

That's correct. So, just fire away.

There is no better option than to use Twitter Ads, Facebook Ads, and Linkedin Ads.
People using these social media platforms (Twitter, Facebook, and Linkedin) will get to know about your mobile app through ads, and they may think of giving it a try - by installing it!

Except those adwords is always a good alternative.