How to promote iOS app?
submit your app for review on websites mobilestartupz.com 148apps.com Add your app as an alternative alternativeto.net is a website to list apps and software tools and their alternatives. Submit your app as an alternative to some categories of apps or a specific app.
Reddit Announce that your app is alive and they can use it for blah blah blah. Post to threads that are probably want your app functionality.